diff --git a/langchain4j/src/main/java/dev/langchain4j/store/embedding/inmemory/InMemoryEmbeddingStore.java b/langchain4j/src/main/java/dev/langchain4j/store/embedding/inmemory/InMemoryEmbeddingStore.java
index 4b3cbc4edf..42411a5731 100644
--- a/langchain4j/src/main/java/dev/langchain4j/store/embedding/inmemory/InMemoryEmbeddingStore.java
+++ b/langchain4j/src/main/java/dev/langchain4j/store/embedding/inmemory/InMemoryEmbeddingStore.java
@@ -23,6 +23,7 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.PriorityQueue;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * An {@link EmbeddingStore} that stores embeddings in memory.
@@ -66,7 +67,7 @@ public int hashCode() {
         }
     }
 
-    private final List<Entry<Embedded>> entries = new ArrayList<>();
+    private final List<Entry<Embedded>> entries = new CopyOnWriteArrayList<>();
 
     @Override
     public String add(Embedding embedding) {