diff --git a/ChangeLog.adoc b/ChangeLog.adoc
index 0d1600685..b51464ccf 100644
--- a/ChangeLog.adoc
+++ b/ChangeLog.adoc
@@ -35,6 +35,7 @@ Bug fixes::
   * irc: add missing tags on self action messages when capability echo-message is enabled (issue #2074)
   * irc: don't strip monospace color code 0x11 from incoming messages (issue #2073)
   * irc: fix random date displayed when a received message contains tags but no "time" (issue #2064)
+  * python: fix truncation of unsigned long long integer returned by function string_parse_size
   * script: always display list of scripts when searching scripts with `/script search` (issue #2077)
   * script: fix default mouse keys (issue #2076)
   * scripts: fix crash on script unload when a hook is created in a buffer close callback (issue #2067)
diff --git a/src/plugins/python/weechat-python-api.c b/src/plugins/python/weechat-python-api.c
index 5cc1ac5f7..068981bdd 100644
--- a/src/plugins/python/weechat-python-api.c
+++ b/src/plugins/python/weechat-python-api.c
@@ -80,8 +80,8 @@
     return PyLong_FromLong ((long)__int)
 #define API_RETURN_LONG(__long)                                         \
     return PyLong_FromLong (__long)
-#define API_RETURN_LONGLONG(__longlong)                                 \
-    return PyLong_FromLongLong (__longlong)
+#define API_RETURN_ULONGLONG(__ulonglong)                               \
+    return PyLong_FromUnsignedLongLong (__ulonglong)
 
 
 /*
@@ -376,14 +376,14 @@ API_FUNC(string_parse_size)
     char *size;
     unsigned long long value;
 
-    API_INIT_FUNC(1, "string_parse_size", API_RETURN_LONGLONG(0));
+    API_INIT_FUNC(1, "string_parse_size", API_RETURN_ULONGLONG(0));
     size = NULL;
     if (!PyArg_ParseTuple (args, "s", &size))
-        API_WRONG_ARGS(API_RETURN_LONGLONG(0));
+        API_WRONG_ARGS(API_RETURN_ULONGLONG(0));
 
     value = weechat_string_parse_size (size);
 
-    API_RETURN_LONGLONG(value);
+    API_RETURN_ULONGLONG(value);
 }
 
 API_FUNC(string_color_code_size)