diff --git a/prody/proteins/pdbclusters.py b/prody/proteins/pdbclusters.py
index 46cee6fdf..b4452543e 100644
--- a/prody/proteins/pdbclusters.py
+++ b/prody/proteins/pdbclusters.py
@@ -106,7 +106,7 @@ def listPDBCluster(pdb, ch, sqid=95):
 def fetchPDBClusters(sqid=None):
     """Retrieve PDB sequence clusters.  PDB sequence clusters are results of
     the weekly clustering of protein chains in the PDB generated by blastclust.
-    They are available at FTP site: ftp://resources.rcsb.org/sequence/clusters/
+    They are available at FTP site: https://cdn.rcsb.org/resources/sequence/clusters/
 
     This function will download about 10 Mb of data and save it after
     compressing in your home directory in :file:`.prody/pdbclusters`.
@@ -135,7 +135,7 @@ def fetchPDBClusters(sqid=None):
     count = 0
     for i, x in enumerate(keys):
         filename = 'bc-{0}.out'.format(x)
-        url = ('ftp://resources.rcsb.org/sequence/clusters/' + filename)
+        url = ('https://cdn.rcsb.org/resources/sequence/clusters/' + filename)
         try:
             inp = openURL(url)
         except IOError: