diff --git a/README.rst b/README.rst
index 96d4ad1..fb8beb0 100644
--- a/README.rst
+++ b/README.rst
@@ -136,6 +136,9 @@ Environment variables
    API.
 -  *SSL_VERIFY*: set to ‘0’ to deactivate SSL verification when talking
    to the DLRN API.
+-  *SSL_CA_BUNDLE*: when set to a value, it will instruct the client to
+   use that file to verify SSL certificates, instead of the default CA
+   bundle provided by `certifi`.
 
 Author
 ------
diff --git a/dlrnapi_client/configuration.py b/dlrnapi_client/configuration.py
index f0d9e69..fae22b2 100644
--- a/dlrnapi_client/configuration.py
+++ b/dlrnapi_client/configuration.py
@@ -82,7 +82,9 @@ def __init__(self):
         else:
             self.verify_ssl = True
         # Set this to customize the certificate file to verify the peer.
-        self.ssl_ca_cert = None
+        # If SSL_CA_BUNDLE is not set, self.ssl_ca_cert will be None,
+        # so we will use the CA bundle provided by certifi
+        self.ssl_ca_cert = os.environ.get('SSL_CA_BUNDLE')
         # client certificate file
         self.cert_file = None
         # client key file