diff --git a/sys/riscv/include/riscvreg.h b/sys/riscv/include/riscvreg.h
index 6984ab118ab5..b18df1798446 100644
--- a/sys/riscv/include/riscvreg.h
+++ b/sys/riscv/include/riscvreg.h
@@ -124,7 +124,6 @@
 #define	XLEN		8
 #define	INSN_SIZE	4
 
-#define	INSN_SIZE		4
 #define	RISCV_INSN_NOP		0x00000013
 #define	RISCV_INSN_BREAK	0x00100073
 #define	RISCV_INSN_RET		0x00008067