diff --git a/pkg/parquetconverter/converter.go b/pkg/parquetconverter/converter.go
index bcfd8237d71..d0ce910ca14 100644
--- a/pkg/parquetconverter/converter.go
+++ b/pkg/parquetconverter/converter.go
@@ -386,7 +386,8 @@ func (c *Converter) convertUser(ctx context.Context, logger log.Logger, ring rin
 			continue
 		}
 
-		if marker.Version == cortex_parquet.CurrentVersion {
+		// We don't convert blocks again if they already have a valid converter mark.
+		if cortex_parquet.ValidConverterMarkVersion(marker.Version) {
 			continue
 		}
 
diff --git a/pkg/parquetconverter/converter_test.go b/pkg/parquetconverter/converter_test.go
index 46c9c4b18b8..03a96a68cf2 100644
--- a/pkg/parquetconverter/converter_test.go
+++ b/pkg/parquetconverter/converter_test.go
@@ -1,7 +1,9 @@
 package parquetconverter
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -414,3 +416,71 @@ func (m *mockTenantLimits) ByUserID(userID string) *validation.Limits {
 func (m *mockTenantLimits) AllByUserID() map[string]*validation.Limits {
 	return m.limits
 }
+
+func TestConverter_SkipBlocksWithExistingValidMarker(t *testing.T) {
+	cfg := prepareConfig()
+	user := "user"
+	ringStore, closer := consul.NewInMemoryClient(ring.GetCodec(), log.NewNopLogger(), nil)
+	t.Cleanup(func() { assert.NoError(t, closer.Close()) })
+	dir := t.TempDir()
+
+	cfg.Ring.InstanceID = "parquet-converter-1"
+	cfg.Ring.InstanceAddr = "1.2.3.4"
+	cfg.Ring.KVStore.Mock = ringStore
+	bucketClient, err := filesystem.NewBucket(t.TempDir())
+	require.NoError(t, err)
+	userBucket := bucket.NewPrefixedBucketClient(bucketClient, user)
+	limits := &validation.Limits{}
+	flagext.DefaultValues(limits)
+	limits.ParquetConverterEnabled = true
+
+	c, logger, _ := prepare(t, cfg, objstore.WithNoopInstr(bucketClient), limits, nil)
+
+	ctx := context.Background()
+
+	lbls := labels.FromStrings("__name__", "test")
+
+	// Create a block
+	rnd := rand.New(rand.NewSource(time.Now().Unix()))
+	blockID, err := e2e.CreateBlock(ctx, rnd, dir, []labels.Labels{lbls}, 2, 0, 2*time.Hour.Milliseconds(), time.Minute.Milliseconds(), 10)
+	require.NoError(t, err)
+
+	// Upload the block to the bucket
+	blockDir := fmt.Sprintf("%s/%s", dir, blockID.String())
+	b, err := tsdb.OpenBlock(nil, blockDir, nil, nil)
+	require.NoError(t, err)
+	err = block.Upload(ctx, logger, userBucket, b.Dir(), metadata.NoneFunc)
+	require.NoError(t, err)
+
+	// Write a converter mark with version 1 to simulate an already converted block
+	markerV1 := parquet.ConverterMark{
+		Version: parquet.ParquetConverterMarkVersion1,
+	}
+	markerBytes, err := json.Marshal(markerV1)
+	require.NoError(t, err)
+	markerPath := path.Join(blockID.String(), parquet.ConverterMarkerFileName)
+	err = userBucket.Upload(ctx, markerPath, bytes.NewReader(markerBytes))
+	require.NoError(t, err)
+
+	// Verify the marker exists with version 1
+	marker, err := parquet.ReadConverterMark(ctx, blockID, userBucket, logger)
+	require.NoError(t, err)
+	require.Equal(t, parquet.ParquetConverterMarkVersion1, marker.Version)
+
+	// Start the converter
+	err = services.StartAndAwaitRunning(context.Background(), c)
+	require.NoError(t, err)
+	defer services.StopAndAwaitTerminated(ctx, c) // nolint:errcheck
+
+	// Wait a bit for the converter to process blocks
+	time.Sleep(5 * time.Second)
+
+	// Verify the marker version is still 1 (i.e., the block was not converted again)
+	markerAfter, err := parquet.ReadConverterMark(ctx, blockID, userBucket, logger)
+	require.NoError(t, err)
+	require.Equal(t, parquet.ParquetConverterMarkVersion1, markerAfter.Version, "block with existing marker version 1 should not be converted again")
+
+	// Verify that no conversion happened by checking the convertedBlocks metric
+	// It should be 0 since the block was already converted
+	assert.Equal(t, 0.0, testutil.ToFloat64(c.metrics.convertedBlocks.WithLabelValues(user)))
+}
diff --git a/pkg/storage/parquet/converter_marker.go b/pkg/storage/parquet/converter_marker.go
index 380b4244fed..4aeb41ebdfa 100644
--- a/pkg/storage/parquet/converter_marker.go
+++ b/pkg/storage/parquet/converter_marker.go
@@ -19,7 +19,12 @@ import (
 const (
 	ConverterMarkerPrefix   = "parquet-markers"
 	ConverterMarkerFileName = "parquet-converter-mark.json"
-	CurrentVersion          = 1
+
+	CurrentVersion               = ParquetConverterMarkVersion2
+	ParquetConverterMarkVersion1 = 1
+	// ParquetConverterMarkVersion2 has an additional series hash
+	// column which is used for projection pushdown.
+	ParquetConverterMarkVersion2 = 2
 )
 
 type ConverterMark struct {
@@ -64,3 +69,7 @@ func WriteConverterMark(ctx context.Context, id ulid.ULID, userBkt objstore.Buck
 type ConverterMarkMeta struct {
 	Version int `json:"version"`
 }
+
+func ValidConverterMarkVersion(version int) bool {
+	return version == ParquetConverterMarkVersion1 || version == ParquetConverterMarkVersion2
+}