diff --git a/bin/comps_filter b/bin/comps_filter
index 107214d4..67e568a5 100755
--- a/bin/comps_filter
+++ b/bin/comps_filter
@@ -142,7 +142,7 @@ class CompsFilter(object):
 
     def write(self, file_obj):
         self.tree.write(file_obj, pretty_print=self.reindent, xml_declaration=True, encoding=self.encoding)
-        file_obj.write("\n")
+        file_obj.write(b"\n")
 
 
 def main():
@@ -174,8 +174,8 @@ def main():
 
     opts = parser.parse_args()
 
-    file_obj = open(opts.comps_file, "r")
-    f = CompsFilter(file_obj, reindent=not opts.no_reindent)
+    with open(opts.comps_file, "rb") as file_obj:
+        f = CompsFilter(file_obj, reindent=not opts.no_reindent)
     f.filter_packages(opts.arch, opts.arch_only_packages)
     f.filter_groups(opts.arch, opts.arch_only_groups)
     f.filter_environments(opts.arch, opts.arch_only_environments)
@@ -199,7 +199,7 @@ def main():
     if opts.remove_environments:
         f.remove_environments()
 
-    f.write(open(opts.output, 'w') if opts.output else sys.stdout)
+    f.write(open(opts.output, 'wb') if opts.output else sys.stdout)
 
 
 if __name__ == "__main__":
diff --git a/pungi/phases/pkgset/sources/source_koji.py b/pungi/phases/pkgset/sources/source_koji.py
index 8034926f..ab08fe5b 100644
--- a/pungi/phases/pkgset/sources/source_koji.py
+++ b/pungi/phases/pkgset/sources/source_koji.py
@@ -205,7 +205,8 @@ def populate_global_pkgset(compose, koji_wrapper, path_prefix, event_id):
     if compose.DEBUG and os.path.isfile(global_pkgset_path):
         msg = "Populating the global package set from tag '%s'" % compose_tags
         compose.log_warning("[SKIP ] %s" % msg)
-        global_pkgset = pickle.load(open(global_pkgset_path, "r"))
+        with open(global_pkgset_path, "rb") as f:
+            global_pkgset = pickle.load(f)
     else:
         global_pkgset = pungi.phases.pkgset.pkgsets.KojiPackageSet(
             koji_wrapper, compose.conf["sigkeys"], logger=compose._logger,
@@ -239,8 +240,9 @@ def populate_global_pkgset(compose, koji_wrapper, path_prefix, event_id):
                 global_pkgset = pkgset
             else:
                 global_pkgset.merge(pkgset, None, list(all_arches))
-        with open(global_pkgset_path, 'w') as f:
-            f.write(pickle.dumps(global_pkgset))
+        with open(global_pkgset_path, 'wb') as f:
+            data = pickle.dumps(global_pkgset)
+            f.write(data)
 
     # write global package list
     global_pkgset.save_file_list(
diff --git a/pungi/phases/pkgset/sources/source_repos.py b/pungi/phases/pkgset/sources/source_repos.py
index f8e36479..b8ca232d 100644
--- a/pungi/phases/pkgset/sources/source_repos.py
+++ b/pungi/phases/pkgset/sources/source_repos.py
@@ -131,15 +131,14 @@ def populate_global_pkgset(compose, file_list, path_prefix):
     global_pkgset_path = os.path.join(compose.paths.work.topdir(arch="global"), "packages.pickle")
     if compose.DEBUG and os.path.isfile(global_pkgset_path):
         compose.log_warning("[SKIP ] %s" % msg)
-        pkgset = pickle.load(open(global_pkgset_path, "r"))
+        with open(global_pkgset_path, "rb") as f:
+            pkgset = pickle.load(f)
     else:
         compose.log_info(msg)
         pkgset = pungi.phases.pkgset.pkgsets.FilelistPackageSet(compose.conf["sigkeys"], logger=compose._logger, arches=ALL_ARCHES)
         pkgset.populate(file_list)
-        f = open(global_pkgset_path, "w")
-        data = pickle.dumps(pkgset)
-        f.write(data)
-        f.close()
+        with open(global_pkgset_path, "wb") as f:
+            pickle.dump(pkgset, f)
 
     # write global package list
     pkgset.save_file_list(compose.paths.work.package_list(arch="global"), remove_path_prefix=path_prefix)
diff --git a/pungi/wrappers/comps.py b/pungi/wrappers/comps.py
index a392158b..852a6861 100644
--- a/pungi/wrappers/comps.py
+++ b/pungi/wrappers/comps.py
@@ -71,7 +71,7 @@ class CompsWrapper(object):
         if not target_file:
             target_file = self.comps_file
 
-        with open(target_file, "w") as stream:
+        with open(target_file, "wb") as stream:
             stream.write(comps_obj.toprettyxml(indent="  ", encoding="UTF-8"))
 
     def generate_comps(self):
diff --git a/tests/helpers.py b/tests/helpers.py
index 11049935..be6ac6d9 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -141,7 +141,7 @@ def touch(path, content=None):
         os.makedirs(os.path.dirname(path))
     except OSError:
         pass
-    with open(path, 'w') as f:
+    with open(path, 'wb') as f:
         f.write(content)
     return path