diff --git a/packages/sdk/src/cosmwasmclient.ts b/packages/sdk/src/cosmwasmclient.ts
index 0f7a51b2..126e3b69 100644
--- a/packages/sdk/src/cosmwasmclient.ts
+++ b/packages/sdk/src/cosmwasmclient.ts
@@ -105,6 +105,7 @@ export interface ContractDetails extends Contract {
 /** A transaction that is indexed as part of the transaction history */
 export interface IndexedTx {
   readonly height: number;
+  /** Transaction hash (might be used as transaction ID). Guaranteed to be non-empty upper-case hex */
   readonly hash: string;
   readonly rawLog: string;
   readonly logs: readonly Log[];
diff --git a/packages/sdk/types/cosmwasmclient.d.ts b/packages/sdk/types/cosmwasmclient.d.ts
index e7ffa3d4..4b92801b 100644
--- a/packages/sdk/types/cosmwasmclient.d.ts
+++ b/packages/sdk/types/cosmwasmclient.d.ts
@@ -74,6 +74,7 @@ export interface ContractDetails extends Contract {
 /** A transaction that is indexed as part of the transaction history */
 export interface IndexedTx {
   readonly height: number;
+  /** Transaction hash (might be used as transaction ID). Guaranteed to be non-empty upper-case hex */
   readonly hash: string;
   readonly rawLog: string;
   readonly logs: readonly Log[];