diff --git a/src/awaitility_clj/core.clj b/src/awaitility_clj/core.clj
index bd3a4b9..1a79e6f 100644
--- a/src/awaitility_clj/core.clj
+++ b/src/awaitility_clj/core.clj
@@ -23,6 +23,7 @@
   [^ConditionFactory factory [option-key option-data]]
   (case option-key
     :at-most (.atMost factory ^Duration (tuple->duration option-data))
+    :at-least (.atLeast factory ^Duration (tuple->duration option-data))
     :poll-interval (.pollInterval factory ^Duration (tuple->duration option-data))))
 
 (defn- apply-options
diff --git a/test/awaitility_clj/core_test.clj b/test/awaitility_clj/core_test.clj
index 28ca4bb..6971e5f 100644
--- a/test/awaitility_clj/core_test.clj
+++ b/test/awaitility_clj/core_test.clj
@@ -18,12 +18,24 @@
   (testing "wait-for throws ConditionTimeoutException if condition times out"
     (let [start-time (System/currentTimeMillis)
           end-time (+ start-time 1500)]
-      (is (thrown?
+      (is (thrown-with-msg?
             ConditionTimeoutException
+            #"was not fulfilled within"
             (wait-for
               {:at-most [200 :milliseconds]}
               (fn [] (>= (System/currentTimeMillis) end-time))))))))
 
+(deftest wait-for-throws-exception-if-finished-before-at-least
+  (testing "wait-for throws ConditionTimeoutException if condition happens before given at-least parameter"
+    (let [start-time (System/currentTimeMillis)
+          end-time (+ start-time 100)]
+      (is (thrown-with-msg?
+            ConditionTimeoutException
+            #"milliseconds which is earlier than expected minimum timeout 500 milliseconds"
+            (wait-for
+              {:at-least [500 :milliseconds]}
+              (fn [] (>= (System/currentTimeMillis) end-time))))))))
+
 (deftest wait-for-poll-intervals
   (testing "wait-for uses default poll interval if none set"
     (let [start-time (System/currentTimeMillis)