diff --git a/CHANGELOG.md b/CHANGELOG.md
index ab2963fcf5..24206ec32b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#7843](https://github.com/thanos-io/thanos/pull/7843) Query Frontend: fix slow query logging for non-query endpoints.
 - [#7852](https://github.com/thanos-io/thanos/pull/7852) Query Frontend: pass "stats" parameter forward to queriers and fix Prometheus stats merging.
 - [#7832](https://github.com/thanos-io/thanos/pull/7832) Query Frontend: Fix cache keys for dynamic split intervals.
+- [#7885](https://github.com/thanos-io/thanos/pull/7885) Store: Return chunks to the pool after completing a Series call.
 
 ### Added
 - [#7763](https://github.com/thanos-io/thanos/pull/7763) Ruler: use native histograms for client latency metrics.
diff --git a/pkg/store/bucket.go b/pkg/store/bucket.go
index 7ab47f4cbe..eec1de1005 100644
--- a/pkg/store/bucket.go
+++ b/pkg/store/bucket.go
@@ -1688,10 +1688,12 @@ func (s *BucketStore) Series(req *storepb.SeriesRequest, seriesSrv storepb.Store
 		s.metrics.seriesBlocksQueried.WithLabelValues(tenant).Observe(float64(stats.blocksQueried))
 	}
 
+	lt := NewProxyResponseLoserTree(respSets...)
+	defer lt.Close()
 	// Merge the sub-results from each selected block.
 	tracing.DoInSpan(ctx, "bucket_store_merge_all", func(ctx context.Context) {
 		begin := time.Now()
-		set := NewResponseDeduplicator(NewProxyResponseLoserTree(respSets...))
+		set := NewResponseDeduplicator(lt)
 		i := 0
 		for set.Next() {
 			i++