This paper presents an efficient decoding algorithm for raptor codes which are widely used for multimedia broadcast services. Decoding raptor codes is the recovery of the source symbols from the received encoding symbols transmitted through an erasure channel. If the received encoding symbols are insufficient to recover the source symbols, additional encoding symbols are delivered and decoded with the previously received encoding symbols. We propose a low complexity raptor decoding algorithm which efficiently combines the previously received encoding symbols and incremental encoding symbols. The proposed algorithm has excellent potential for realizing low power operation for multimedia broadcast services, due to its highly reduced computational complexity.