diff --git a/ChangeLog.d/mbedtls_x509_time.txt b/ChangeLog.d/mbedtls_x509_time.txt
index 3eacc29..557f191 100644
--- a/ChangeLog.d/mbedtls_x509_time.txt
+++ b/ChangeLog.d/mbedtls_x509_time.txt
@@ -1,2 +1,3 @@
 Features
    * Improve mbedtls_x509_time performance and reduce memory use.
+   * Reduce syscalls to time() during certificate verification.
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 9b3414a..43e1aa2 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -2021,7 +2021,8 @@
  */
 static int x509_crt_verifycrl(mbedtls_x509_crt *crt, mbedtls_x509_crt *ca,
                               mbedtls_x509_crl *crl_list,
-                              const mbedtls_x509_crt_profile *profile)
+                              const mbedtls_x509_crt_profile *profile,
+                              const mbedtls_x509_time *now)
 {
     int flags = 0;
     unsigned char hash[MBEDTLS_MD_MAX_SIZE];
@@ -2099,16 +2100,20 @@
             break;
         }
 
+#if defined(MBEDTLS_HAVE_TIME_DATE)
         /*
          * Check for validity of CRL (Do not drop out)
          */
-        if (mbedtls_x509_time_is_past(&crl_list->next_update)) {
+        if (mbedtls_x509_time_cmp(&crl_list->next_update, now) < 0) {
             flags |= MBEDTLS_X509_BADCRL_EXPIRED;
         }
 
-        if (mbedtls_x509_time_is_future(&crl_list->this_update)) {
+        if (mbedtls_x509_time_cmp(&crl_list->this_update, now) > 0) {
             flags |= MBEDTLS_X509_BADCRL_FUTURE;
         }
+#else
+        ((void) now);
+#endif
 
         /*
          * Check if certificate is revoked
@@ -2266,7 +2271,8 @@
     int top,
     unsigned path_cnt,
     unsigned self_cnt,
-    mbedtls_x509_crt_restart_ctx *rs_ctx)
+    mbedtls_x509_crt_restart_ctx *rs_ctx,
+    const mbedtls_x509_time *now)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_x509_crt *parent, *fallback_parent;
@@ -2329,9 +2335,10 @@
             continue;
         }
 
+#if defined(MBEDTLS_HAVE_TIME_DATE)
         /* optional time check */
-        if (mbedtls_x509_time_is_past(&parent->valid_to) ||
-            mbedtls_x509_time_is_future(&parent->valid_from)) {
+        if (mbedtls_x509_time_cmp(&parent->valid_to, now) < 0 ||    /* past */
+            mbedtls_x509_time_cmp(&parent->valid_from, now) > 0) {  /* future */
             if (fallback_parent == NULL) {
                 fallback_parent = parent;
                 fallback_signature_is_good = signature_is_good;
@@ -2339,6 +2346,9 @@
 
             continue;
         }
+#else
+        ((void) now);
+#endif
 
         *r_parent = parent;
         *r_signature_is_good = signature_is_good;
@@ -2384,7 +2394,8 @@
     int *signature_is_good,
     unsigned path_cnt,
     unsigned self_cnt,
-    mbedtls_x509_crt_restart_ctx *rs_ctx)
+    mbedtls_x509_crt_restart_ctx *rs_ctx,
+    const mbedtls_x509_time *now)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_x509_crt *search_list;
@@ -2405,7 +2416,7 @@
         ret = x509_crt_find_parent_in(child, search_list,
                                       parent, signature_is_good,
                                       *parent_is_trusted,
-                                      path_cnt, self_cnt, rs_ctx);
+                                      path_cnt, self_cnt, rs_ctx, now);
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
         if (rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS) {
@@ -2526,6 +2537,13 @@
     int signature_is_good;
     unsigned self_cnt;
     mbedtls_x509_crt *cur_trust_ca = NULL;
+    mbedtls_x509_time now;
+
+#if defined(MBEDTLS_HAVE_TIME_DATE)
+    if (mbedtls_x509_time_gmtime(mbedtls_time(NULL), &now) != 0) {
+        return MBEDTLS_ERR_X509_FATAL_ERROR;
+    }
+#endif
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
     /* resume if we had an operation in progress */
@@ -2556,14 +2574,16 @@
         ver_chain->len++;
         flags = &cur->flags;
 
+#if defined(MBEDTLS_HAVE_TIME_DATE)
         /* Check time-validity (all certificates) */
-        if (mbedtls_x509_time_is_past(&child->valid_to)) {
+        if (mbedtls_x509_time_cmp(&child->valid_to, &now) < 0) {
             *flags |= MBEDTLS_X509_BADCERT_EXPIRED;
         }
 
-        if (mbedtls_x509_time_is_future(&child->valid_from)) {
+        if (mbedtls_x509_time_cmp(&child->valid_from, &now) > 0) {
             *flags |= MBEDTLS_X509_BADCERT_FUTURE;
         }
+#endif
 
         /* Stop here for trusted roots (but not for trusted EE certs) */
         if (child_is_trusted) {
@@ -2614,7 +2634,8 @@
         /* Look for a parent in trusted CAs or up the chain */
         ret = x509_crt_find_parent(child, cur_trust_ca, &parent,
                                    &parent_is_trusted, &signature_is_good,
-                                   ver_chain->len - 1, self_cnt, rs_ctx);
+                                   ver_chain->len - 1, self_cnt, rs_ctx,
+                                   &now);
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
         if (rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS) {
@@ -2663,7 +2684,7 @@
 
 #if defined(MBEDTLS_X509_CRL_PARSE_C)
         /* Check trusted CA's CRL for the given crt */
-        *flags |= x509_crt_verifycrl(child, parent, ca_crl, profile);
+        *flags |= x509_crt_verifycrl(child, parent, ca_crl, profile, &now);
 #else
         (void) ca_crl;
 #endif