diff --git a/spec/operators/throttleTime-spec.ts b/spec/operators/throttleTime-spec.ts
index e668c9b9c7..a017237ad1 100644
--- a/spec/operators/throttleTime-spec.ts
+++ b/spec/operators/throttleTime-spec.ts
@@ -49,63 +49,110 @@ describe('Observable.prototype.throttleTime', () => {
   it('should simply mirror the source if values are not emitted often enough', () => {
     const e1 =   hot('-a--------b-----c----|');
     const subs =     '^                    !';
+    const t =   time('-----|                ');
     const expected = '-a--------b-----c----|';
 
-    expectObservable(e1.throttleTime(50, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
-  it('should handle a busy producer emitting a regular repeating sequence', () => {
-    const e1 =   hot('abcdefabcdefabcdefabcdefa|');
-    const subs =     '^                        !';
-    const expected = 'a-----a-----a-----a-----a|';
+  it('should handle a busy producer emitting a regular repeating sequence with leading: true, trailing: false', () => {
+    const e1 =   hot('a12345b12345c12345d123|');
+    const subs =     '^                     !';
+    const t =   time('-----|                 ');
+    const expected = 'a-----b-----c-----d---|';
 
-    expectObservable(e1.throttleTime(50, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler, {leading: true, trailing: false})).toBe(expected);
+    expectSubscriptions(e1.subscriptions).toBe(subs);
+  });
+
+  it('should handle a busy producer emitting a regular repeating sequence with leading: true, trailing: true', () => {
+    const e1 =   hot('a1234b1234c1234d12e--|');
+    const subs =     '^                    !';
+    const t =   time('-----|                ');
+    const expected = 'a----b----c----d----e|';
+
+    expectObservable(e1.throttleTime(t, rxTestScheduler, {leading: true, trailing: true})).toBe(expected);
+    expectSubscriptions(e1.subscriptions).toBe(subs);
+  });
+
+  it('should not drop values if values are far apart with leading: true, trailing: true', () => {
+    const e1 =   hot('ab-----------c|');
+    const subs =     '^             !';
+    const t =   time('-----|         ');
+    const expected = 'a----b-------c|';
+
+    expectObservable(e1.throttleTime(t, rxTestScheduler, {leading: true, trailing: true})).toBe(expected);
+    expectSubscriptions(e1.subscriptions).toBe(subs);
+  });
+
+  it('should handle a busy producer emitting a regular repeating sequence with leading: false, trailing: true', () => {
+    const e1 =   hot('12345a1234b1234c12d--|');
+    const subs =     '^                    !';
+    const t =   time('-----|                ');
+    const expected = '-----a----b----c----d|';
+
+    expectObservable(e1.throttleTime(t, rxTestScheduler, {leading: false, trailing: true})).toBe(expected);
+    expectSubscriptions(e1.subscriptions).toBe(subs);
+  });
+
+  it('should only emit trailing values with leading: false, trailing: true', () => {
+    const e1 =   hot('ab-----------c--d--|');
+    const subs =     '^                  !';
+    const t =   time('-----|              ');
+    const expected = '-----b------------d|';
+
+    expectObservable(e1.throttleTime(t, rxTestScheduler, {leading: false, trailing: true})).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
   it('should complete when source does not emit', () => {
     const e1 =   hot('-----|');
     const subs =     '^    !';
+    const t =   time('-----|');
     const expected = '-----|';
 
-    expectObservable(e1.throttleTime(50, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
   it('should raise error when source does not emit and raises error', () => {
     const e1 =   hot('-----#');
     const subs =     '^    !';
+    const t =   time('|     ');
     const expected = '-----#';
 
-    expectObservable(e1.throttleTime(10, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
   it('should handle an empty source', () => {
     const e1 =  cold('|');
     const subs =     '(^!)';
+    const t =   time('---|');
     const expected = '|';
 
-    expectObservable(e1.throttleTime(30, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
   it('should handle a never source', () => {
     const e1 =  cold('-');
     const subs =     '^';
+    const t =   time('---|');
     const expected = '-';
 
-    expectObservable(e1.throttleTime(30, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
   it('should handle a throw source', () => {
     const e1 =  cold('#');
     const subs =     '(^!)';
+    const t =   time('---|');
     const expected = '#';
 
-    expectObservable(e1.throttleTime(30, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
@@ -113,9 +160,10 @@ describe('Observable.prototype.throttleTime', () => {
     const e1 =   hot('-a--(bc)-------d----------------');
     const unsub =    '                               !';
     const subs =     '^                              !';
+    const t =   time('-----|                          ');
     const expected = '-a-------------d----------------';
 
-    expectObservable(e1.throttleTime(50, rxTestScheduler), unsub).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler), unsub).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
@@ -123,11 +171,12 @@ describe('Observable.prototype.throttleTime', () => {
     const e1 =   hot('-a--(bc)-------d----------------');
     const subs =     '^                              !';
     const expected = '-a-------------d----------------';
+    const t =   time('-----|                          ');
     const unsub =    '                               !';
 
     const result = e1
       .mergeMap((x: string) => Observable.of(x))
-      .throttleTime(50, rxTestScheduler)
+      .throttleTime(t, rxTestScheduler)
       .mergeMap((x: string) => Observable.of(x));
 
     expectObservable(result, unsub).toBe(expected);
@@ -137,18 +186,19 @@ describe('Observable.prototype.throttleTime', () => {
   it('should throttle values until source raises error', () => {
     const e1 =   hot('-a--(bc)-------d---------------#');
     const subs =     '^                              !';
+    const t =   time('-----|                          ');
     const expected = '-a-------------d---------------#';
 
-    expectObservable(e1.throttleTime(50, rxTestScheduler)).toBe(expected);
+    expectObservable(e1.throttleTime(t, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
 
   describe('throttleTime(fn, { leading: true, trailing: true })', () => {
     asDiagram('throttleTime(fn, { leading: true, trailing: true })')('should immediately emit the first value in each time window', () =>  {
-      const e1 =   hot('-a-xy-----b--x--cxxx--|');
-      const e1subs =   '^                     !';
-      const t =  time( '----|                 ');
-      const expected = '-a---y----b---x-c---x-|';
+      const e1 =   hot('-a-xy-----b--x--cxxx---|');
+      const e1subs =   '^                      !';
+      const t =  time( '----|                   ');
+      const expected = '-a---y----b---x---x---x|';
 
       const result = e1.throttleTime(t, rxTestScheduler, { leading: true, trailing: true });
 
@@ -158,11 +208,11 @@ describe('Observable.prototype.throttleTime', () => {
   });
 
   describe('throttleTime(fn, { leading: false, trailing: true })', () => {
-    asDiagram('throttleTime(fn, { leading: false, trailing: true })')('should immediately emit the first value in each time window', () =>  {
-      const e1 =   hot('-a-xy-----b--x--cxxx--|');
-      const e1subs =   '^                     !';
-      const t =  time( '----|                 ');
-      const expected = '-----y--------x-----x-|';
+    asDiagram('throttleTime(fn, { leading: false, trailing: true })')('should emit last given value in each time window', () =>  {
+      const e1 =   hot('-a-xy-----b--x--cxcd---|');
+      const e1subs =   '^                      !';
+      const t =  time( '----|                   ');
+      const expected = '-----y--------x---c---d|';
 
       const result = e1.throttleTime(t, rxTestScheduler, { leading: false, trailing: true });
 
diff --git a/src/operators/throttleTime.ts b/src/operators/throttleTime.ts
index d81920a38d..fe6f151c7f 100644
--- a/src/operators/throttleTime.ts
+++ b/src/operators/throttleTime.ts
@@ -85,30 +85,37 @@ class ThrottleTimeSubscriber<T> extends Subscriber<T> {
   }
 
   protected _next(value: T) {
-    if (this.throttled) {
-      if (this.trailing) {
-        this._trailingValue = value;
-        this._hasTrailingValue = true;
-      }
-    } else {
-      this.add(this.throttled = this.scheduler.schedule(dispatchNext, this.duration, { subscriber: this }));
-      if (this.leading) {
-        this.destination.next(value);
-      }
+    if (!this.throttled && this.leading) {
+      this.throttle();
+      this.destination.next(value);
+    } else if (this.trailing) {
+      this._trailingValue = value;
+      this._hasTrailingValue = true;
+    }
+
+    if (!this.throttled) {
+      this.throttle();
     }
   }
 
+  private throttle(): void {
+    this.add(this.throttled = this.scheduler.schedule(dispatchNext, this.duration, { subscriber: this }));
+  }
+
   clearThrottle() {
     const throttled = this.throttled;
+
     if (throttled) {
+      throttled.unsubscribe();
+      this.throttled = null;
+
       if (this.trailing && this._hasTrailingValue) {
-        this.destination.next(this._trailingValue);
+        const trailingValue = this._trailingValue;
         this._trailingValue = null;
         this._hasTrailingValue = false;
+        this.throttle();
+        this.destination.next(trailingValue);
       }
-      throttled.unsubscribe();
-      this.remove(throttled);
-      this.throttled = null;
     }
   }
 }