diff --git a/service.go b/service.go
index 25ea516..33295da 100644
--- a/service.go
+++ b/service.go
@@ -18,6 +18,8 @@ import (
 // ServiceOption configures a Service instance.
 type ServiceOption func(*Service) error
 
+const InvalidPid = -1
+
 // Display specifies the value to which set the DISPLAY environment variable,
 // as well as the path to the Xauthority file containing credentials needed to
 // write to that X server.
@@ -164,6 +166,15 @@ func (s Service) FrameBuffer() *FrameBuffer {
 	return s.xvfb
 }
 
+//PID returns the service pid
+func (s Service) PID() int {
+	if s.cmd != nil {
+		return s.cmd.Process.Pid
+	}
+
+	return InvalidPid
+}
+
 // NewSeleniumService starts a Selenium instance in the background.
 func NewSeleniumService(jarPath string, port int, opts ...ServiceOption) (*Service, error) {
 	s, err := newService(exec.Command("java"), "/wd/hub", port, opts...)