diff --git a/requirements-basic.txt b/requirements-basic.txt
index 823591b7f..a7154ed5b 100644
--- a/requirements-basic.txt
+++ b/requirements-basic.txt
@@ -15,7 +15,7 @@ terminaltables
 pyparsing
 cycler
 requests>=2.4.3
-flask
+flask<2.0.0
 flask_restplus
 cheroot
 validators==0.14.0
diff --git a/setup.py b/setup.py
index 38925a40a..f86dec3d4 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@
     "numpy",
     "scipy",
     "requests>=2.4.3",
-    "flask",
+    "flask<2.0.0",
     "flask_restplus",
     "cheroot",
     "validators==0.14.0",