diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3de5d04d46f..c326dd20162 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 * [ENHANCEMENT] Experimental TSDB: Added `cortex_querier_blocks_meta_synced`, which reflects current state of synced blocks over all tenants. #2392
 * [ENHANCEMENT] Added `cortex_distributor_latest_seen_sample_timestamp_seconds` metric to see how far behind Prometheus servers are in sending data. #2371
 * [ENHANCEMENT] FIFO cache to support eviction based on memory usage. The `-<prefix>.fifocache.size` CLI flag has been renamed to `-<prefix>.fifocache.max-size-items` as well as its YAML config option `size` renamed to `max_size_items`. Added `-<prefix>.fifocache.max-size-bytes` CLI flag and YAML config option `max_size_bytes` to specify memory limit of the cache. #2319
+* [BUGFIX] Experimental TSDB: fixed chunk data corruption when querying back series using the experimental blocks storage. #2400
 
 ## 1.0.0 / 2020-04-02
 
diff --git a/pkg/querier/blocks_bucket_store_inmemory_server.go b/pkg/querier/blocks_bucket_store_inmemory_server.go
index cb4862739bc..8300b12982c 100644
--- a/pkg/querier/blocks_bucket_store_inmemory_server.go
+++ b/pkg/querier/blocks_bucket_store_inmemory_server.go
@@ -30,8 +30,22 @@ func (s *bucketStoreSeriesServer) Send(r *storepb.SeriesResponse) error {
 		s.Warnings = append(s.Warnings, errors.New(r.GetWarning()))
 	}
 
-	if r.GetSeries() != nil {
-		s.SeriesSet = append(s.SeriesSet, r.GetSeries())
+	if recvSeries := r.GetSeries(); recvSeries != nil {
+		// Thanos uses a pool for the chunks and may use other pools in the future.
+		// Given we need to retain the reference after the pooled slices are recycled,
+		// we need to do a copy here. We prefer to stay on the safest side at this stage
+		// so we do a marshal+unmarshal to copy the whole series.
+		recvSeriesData, err := recvSeries.Marshal()
+		if err != nil {
+			return errors.Wrap(err, "marshal received series")
+		}
+
+		copiedSeries := &storepb.Series{}
+		if err = copiedSeries.Unmarshal(recvSeriesData); err != nil {
+			return errors.Wrap(err, "unmarshal received series")
+		}
+
+		s.SeriesSet = append(s.SeriesSet, copiedSeries)
 	}
 
 	return nil