This paper presents a new adaptive algorithm for speech Compression using Cosine Packet Transform. The proposed algorithm uses packet decomposition, which reduces a computational complexity of a system. This paper compare the compression ratio of methods using Wavelet Transform, Cosine Transform, Wavelet Packet Transform and proposed adaptive algorithm using Cosine Packet Transform for different speech signal samples. The mean compression ratio is calculated for all the methods and compared. The implemented results show that the proposed compression algorithm gives the better performance for speech signals. ©2007 IEEE.