The agency maintained its grip on the £7 million account after a pitch process, run through the AAR, that also involved M2M, Starcom and Universal McCann.
Starcom and M2M were eliminated early this week, leaving a face-off between BLM and Universal McCann. Pathe said at the start of review in March that online would be a key factor in its decision.
John Fletcher, the managing director of Pathe Distribution, said: "BLM made a very convincing pitch and together I'm sure we will have continued success."
Pathe, an independent UK film distributor, handles 20 films a year, some produced by its Pathe Films division.