China's official manufacturing PMI fell to a six-month low in January, dropping to an expected 50.5 from 51 in December.
The reading adds to other data that indicate slowing growth in China, although at least the latest figure shows expansion - HSBC's PMI gauge dropped below 50 to 49.5 and indicated contraction.
The official readings for output and new orders fell, although they still showed growth, while jobs and export orders shrank at a faster pace.
However, part of the decline last month was attributed to the approach of the Lunar New Year, due to production slowing down as people traveled home for the week-long holiday.
Because of the festival, Chinese markets won't be able to react for a number of days.