diff --git a/doc/dev.md b/doc/dev.md
index 4244149e..19f5151e 100644
--- a/doc/dev.md
+++ b/doc/dev.md
@@ -57,6 +57,9 @@ Keep notes here about how adding libraries and classes to Babashka affects the b
 
 <!-- 2020/01/08, ..., 38.7mb / 11.3mb zipped -->
 <!-- Added: `clojure.data.xml`. Growth: 1.8mb / ... -->
+2020/02/21, 
+Added java.time.temporal.ChronoUnit
+40651596 - 40598260 = 53kb added.
 
 2020/02/19, e43727955a2cdabd2bb0189c20dd7f9a18156fc9
 Added fipp.edn/pprint
diff --git a/src/babashka/impl/classes.clj b/src/babashka/impl/classes.clj
index e0451f08..d69a0d9a 100644
--- a/src/babashka/impl/classes.clj
+++ b/src/babashka/impl/classes.clj
@@ -83,6 +83,7 @@
           java.time.ZonedDateTime
           java.time.ZoneId
           java.time.ZoneOffset
+          java.time.temporal.ChronoUnit
           java.time.temporal.TemporalAccessor
           java.util.regex.Pattern
           java.util.Base64
diff --git a/test/babashka/java_time_test.clj b/test/babashka/java_time_test.clj
index 65b22709..c66fb8e4 100644
--- a/test/babashka/java_time_test.clj
+++ b/test/babashka/java_time_test.clj
@@ -16,4 +16,8 @@
   (is (= "18-12-2019 16:01:41"
          (bb '(.format
                (java.time.LocalDateTime/parse "2019-12-18T16:01:41.485")
-               (java.time.format.DateTimeFormatter/ofPattern "dd-MM-yyyy HH:mm:ss"))))))
+               (java.time.format.DateTimeFormatter/ofPattern "dd-MM-yyyy HH:mm:ss")))))
+  (is (number? (bb "
+(let [x (java.time.LocalDateTime/parse \"2019-12-18T16:01:41.485\")
+      y (java.time.LocalDateTime/now)]
+  (.between java.time.temporal.ChronoUnit/MINUTES x y))"))))