diff --git a/esutil/bulk_indexer.go b/esutil/bulk_indexer.go
index c462876562..6618611f33 100644
--- a/esutil/bulk_indexer.go
+++ b/esutil/bulk_indexer.go
@@ -265,6 +265,12 @@ type bulkIndexerStats struct {
 	numRequests uint64
 }
 
+var bufPool = &sync.Pool{
+	New: func() interface{} {
+		return new(bytes.Buffer)
+	},
+}
+
 // NewBulkIndexer creates a new bulk indexer.
 func NewBulkIndexer(cfg BulkIndexerConfig) (BulkIndexer, error) {
 	if cfg.Client == nil {
@@ -337,6 +343,11 @@ func (bi *bulkIndexer) Close(ctx context.Context) error {
 		bi.wg.Wait()
 	}
 
+	for _, w := range bi.workers {
+		w.buf.Reset()
+		bufPool.Put(w.buf)
+	}
+
 	return nil
 }
 
@@ -363,7 +374,7 @@ func (bi *bulkIndexer) init() {
 			id:     i,
 			ch:     bi.queue,
 			bi:     bi,
-			buf:    bytes.NewBuffer(make([]byte, 0, bi.config.FlushBytes)),
+			buf:    bufPool.Get().(*bytes.Buffer),
 			ticker: time.NewTicker(bi.config.FlushInterval),
 		}
 		w.run()