diff --git a/sanic/config.py b/sanic/config.py
index 18514425..853e4a99 100644
--- a/sanic/config.py
+++ b/sanic/config.py
@@ -132,7 +132,7 @@ class Config(dict):
 
         if load_env:
             prefix = SANIC_PREFIX if load_env == True else load_env
-            self.load_environment_vars(prefix=load_env)
+            self.load_environment_vars(prefix=prefix)
 
     def __getattr__(self, attr):
         try:
diff --git a/tests/test_config.py b/tests/test_config.py
index aa7a0e4d..e393d02b 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -19,15 +19,21 @@ def test_load_from_object():
 def test_auto_load_env():
     environ["SANIC_TEST_ANSWER"] = "42"
     app = Sanic()
-    assert app.config.TEST_ANSWER == "42"
+    assert app.config.TEST_ANSWER == 42
     del environ["SANIC_TEST_ANSWER"]
 
-def test_auto_load_env():
+def test_dont_load_env():
     environ["SANIC_TEST_ANSWER"] = "42"
     app = Sanic(load_env=False)
     assert getattr(app.config, 'TEST_ANSWER', None) == None
     del environ["SANIC_TEST_ANSWER"]
 
+def test_load_env_prefix():
+    environ["MYAPP_TEST_ANSWER"] = "42"
+    app = Sanic(load_env='MYAPP_')
+    assert app.config.TEST_ANSWER == 42
+    del environ["MYAPP_TEST_ANSWER"]
+
 def test_load_from_file():
     app = Sanic('test_load_from_file')
     config = b"""