diff --git a/reftable/error.c b/reftable/error.c
index a25f28a43e..660d029617 100644
--- a/reftable/error.c
+++ b/reftable/error.c
@@ -35,6 +35,8 @@ const char *reftable_error_str(int err)
 		return "entry too large";
 	case REFTABLE_OUTDATED_ERROR:
 		return "data concurrently modified";
+	case REFTABLE_OUT_OF_MEMORY_ERROR:
+		return "out of memory";
 	case -1:
 		return "general error";
 	default:
diff --git a/reftable/reftable-error.h b/reftable/reftable-error.h
index 6368cd9ed9..f404826562 100644
--- a/reftable/reftable-error.h
+++ b/reftable/reftable-error.h
@@ -57,6 +57,9 @@ enum reftable_error {
 
 	/* Trying to write out-of-date data. */
 	REFTABLE_OUTDATED_ERROR = -12,
+
+	/* An allocation has failed due to an out-of-memory situation. */
+	REFTABLE_OUT_OF_MEMORY_ERROR = -13,
 };
 
 /* convert the numeric error code to a string. The string should not be