They are not happy that Jose Mourinho failed to attend a compulsory post-match press conference and for Chelsea being late in returning to the pitch for the second half.
A UEFA spokesman said: "We have started a disciplinary case against Chelsea for the late arrival on to the pitch from the dressing room for the second half and the non-appearance of the coach at the post-match media conference.
"We have notified the club that the matter will be dealt with on 24 March and they can can submit a statement to us."
But the Blues will be lodging a complaint of their own - namely that Barcelona coach Frank Rijkaard had a chat with referee Anders Frisk at half-time.
Barcelona were trailing 0-1 at the time, but managed to turn the game round and win the first leg 2-1 with Didier Drogba being sent-off by Frisk for good measure.
The two sides face each other in the second leg on March 8 at Stamford Bridge.