The multicast available bit rate (ABR) service in ATM networks is important for many emerging data service applications. The authors propose a fuzzy-logic-based consolidation algorithm to solve the problems of consolidation noise and delay. The proposed algorithm is composed of the CI analyser, the adaptation law, and the fuzzy predictor. Using the CI analyser, the adaptation law determines an adaptation parameter so that the fuzzy predictor estimates the unknown congestion information. The usefulness of the proposed algorithm is demonstrated by some numerical results.