diff --git a/ntp_core.c b/ntp_core.c
index 7910d23..f2f67af 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -47,11 +47,6 @@
 
 static LOG_FileID logfileid;
 
-/* ================================================== */
-
-/* Day number of 1 Jan 1970 */
-#define MJD_1970 40587
-
 /* ================================================== */
 /* Enumeration used for remembering the operating mode of one of the
    sources */
diff --git a/rtc_linux.c b/rtc_linux.c
index 4c0eb2b..85418a0 100644
--- a/rtc_linux.c
+++ b/rtc_linux.c
@@ -686,9 +686,6 @@ handle_relock_after_trim(void)
 
 /* ================================================== */
 
-/* Day number of 1 Jan 1970 */
-#define MJD_1970 40587
-
 static void
 process_reading(time_t rtc_time, struct timeval *system_time)
 {