diff --git a/drivers/rtc/rtc-as3722.c b/drivers/rtc/rtc-as3722.c
index 9f38eda6..56cc582 100644
--- a/drivers/rtc/rtc-as3722.c
+++ b/drivers/rtc/rtc-as3722.c
@@ -45,7 +45,7 @@
 	rbuff[1] = bin2bcd(tm->tm_min);
 	rbuff[2] = bin2bcd(tm->tm_hour);
 	rbuff[3] = bin2bcd(tm->tm_mday);
-	rbuff[4] = bin2bcd(tm->tm_mon);
+	rbuff[4] = bin2bcd(tm->tm_mon + 1);
 	rbuff[5] = bin2bcd(tm->tm_year - (AS3722_RTC_START_YEAR - 1900));
 }
 
@@ -55,7 +55,7 @@
 	tm->tm_min = bcd2bin(rbuff[1] & 0x7F);
 	tm->tm_hour = bcd2bin(rbuff[2] & 0x3F);
 	tm->tm_mday = bcd2bin(rbuff[3] & 0x3F);
-	tm->tm_mon = bcd2bin(rbuff[4] & 0x1F);
+	tm->tm_mon = bcd2bin(rbuff[4] & 0x1F) - 1;
 	tm->tm_year = (AS3722_RTC_START_YEAR - 1900) + bcd2bin(rbuff[5] & 0x7F);
 	return;
 }