We conducted studies of mass losses from surface and buried litter bags in four North American hot desert areas to test the following hypotheses: (1) leaf litter disappearance in hot deserts is independent of actual evapotranspiration, (2) buried litter disappearance is a function of actual evapotranspiration, (3) the patter of microarthropod colonization of buried leaf litter is a function of the stage of decomposition, and (4) elimination of microarthropod results in reduced rates of decomposition and increased numbers of free-living nematodes.