diff --git a/include/ChangeLog b/include/ChangeLog
index bdde6ea5020..09a3ad960ea 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,8 @@
+2021-02-05  Nelson Chu  <nelson.chu@sifive.com>
+
+	PR 27348
+	* opcode/riscv.h: Remove obsolete OP_*CUSTOM_IMM.
+
 2021-02-05  Nelson Chu  <nelson.chu@sifive.com>
 
 	PR 27348
diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index ab8b717bf10..5432e6ceafe 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -223,8 +223,6 @@ static const char * const riscv_pred_succ[16] =
 #define OP_MASK_RL		0x1
 #define OP_SH_RL		25
 
-#define OP_MASK_CUSTOM_IMM	0x7fU
-#define OP_SH_CUSTOM_IMM	25
 #define OP_MASK_CSR		0xfffU
 #define OP_SH_CSR		20