— Compared with a single level Hamming associative memory, a simple model based on uniform random noise analysis has proved a twolevel decoupled Hamming network to be an efficient associative memory but with a lower capacity against uniform random noise. Introducing concentrated noise, our more detailed analysis shows that the deteriorated capacity of the two-level Hamming associative memory against uniform random noise is actually minor, but that it possesses a substantially increased capacity against concentrated noise which is more prevalent in practice than uniform random noise.