"The so-called Western April Fool's Day does not conform to Chinese cultural traditions or socialist core values," the party's leading propaganda organ, Xinhua News Agency, said in a brief message on its official microblog Friday.
"Hope people won't believe in rumors, start rumors or spread rumors," the message concluded.
People are not really happy with the admonition against jokes and pranks.
Xinhua banned any comments, but people took to other outlets to mock the official party stance.
One said: “Living in China, every day is a Fool’s Day."
Another wrote: "Don’t you think this post itself is the biggest joke?!"
One person posted: “It’s just a day to bring people some fun. Official media wants to get attention, so to publish such post, so stupid.”
Even the official Beijing News newspaper took issue with Xinhua's kill-joy attitude, asking, "what's wrong with giving people a holiday to express themselves, joke around and find some release?"
READ: China punishes 197 people including journalists for spreading rumors online