In the framework of the Atmospheric Model Intercomparison Project (AMIP) a report has been published on the analysis of the seasonal precipitation associated with the African, Indian and the Australian-Indonesian monsoon and the interannual variation of the Indian monsoon. AMIP is conducted by the U.S. Dept. of Energy Programme for Climate Model Diagnosis and Intercomparison (PCMDI) under the auspices of WCRP and WMO. Organized intercomparisons of model simulations are a basic tool in refining atmospheric models for use in climate studies on all time scales and for weather prediction. The reported subproject compares the simulations of thirty atmospheric general circulation models (GCMs). The different models are divided into two classes on the basis of the seasonal variation of the major rainbelt over the Asia West Pacific sector, one class comprising those with a realistic simulation, the second class containing those with a smaller amplitude of seasonal migration than observed. This classification based on seasonal mean patterns was found to be useful for interpreting the simulation of interannual variation.