diff --git a/requirements.txt b/requirements.txt
index 6bad103..f155d82 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,2 @@
-numpy
+numpy==1.18.1
 scipy
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 836e3b2..cc70009 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -1,3 +1,3 @@
-numpy
+numpy==1.18.1
 scipy
 pytest>=5.0.1
\ No newline at end of file