diff --git a/dtls_time.c b/dtls_time.c
index 5d353b4f..c5db861d 100644
--- a/dtls_time.c
+++ b/dtls_time.c
@@ -43,12 +43,12 @@ dtls_tick_t dtls_clock_offset;
 
 void
 dtls_clock_init(void) {
-  dtls_clock_offset = xtimer_now64().ticks64;
+  dtls_clock_offset = ztimer_now(ZTIMER_MSEC);
 }
 
 void
 dtls_ticks(dtls_tick_t *t) {
-  *t = xtimer_now64().ticks64 -dtls_clock_offset;
+  *t = ztimer_now(ZTIMER_MSEC) - dtls_clock_offset;
 }
 
 #endif /* RIOT_VERSION */
diff --git a/dtls_time.h b/dtls_time.h
index 1aafa9a1..a491b0ac 100644
--- a/dtls_time.h
+++ b/dtls_time.h
@@ -42,15 +42,16 @@
 
 #elif defined(RIOT_VERSION)
 
-#include <xtimer.h>
+#include "ztimer.h"
+#include "timex.h"
 
 /* this macro is already present on FreeBSD
    which causes a redefine error otherwise */
 #ifndef CLOCK_SECOND
-#define CLOCK_SECOND (xtimer_ticks_from_usec64(1000000UL).ticks64)
+#define CLOCK_SECOND (MS_PER_SEC)
 #endif
 
-typedef uint64_t clock_time_t;
+typedef uint32_t clock_time_t;
 
 #else /* WITH_CONTIKI || RIOT_VERSION */