diff --git a/environment.yml b/environment.yml
index 325b79f07a61c..ef5767f26dceb 100644
--- a/environment.yml
+++ b/environment.yml
@@ -15,7 +15,7 @@ dependencies:
   - cython>=0.29.13
 
   # code checks
-  - black>=19.10b0
+  - black=19.10b0
   - cpplint
   - flake8
   - flake8-comprehensions>=3.1.0  # used by flake8, linting of unnecessary comprehensions
diff --git a/requirements-dev.txt b/requirements-dev.txt
index f589812e81635..3ae5b57de5d02 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -3,7 +3,7 @@ python-dateutil>=2.6.1
 pytz
 asv
 cython>=0.29.13
-black>=19.10b0
+black==19.10b0
 cpplint
 flake8
 flake8-comprehensions>=3.1.0