Using the cellulose-film method the distribution of mycostasis was examined in profiles from five differing soil types in Malaya. Soils were found to be inhibitory to the spores of Mucor ramannianus Möller to a depth of 360 cm, but waterlogged soils were less inhibitory than those which were drained. The addition of 1% (w/v) glucose only partially masked the inhibition in some soils while autoclaving the soils before assay resulted in a complete removal of the inhibition from the upper soil layers only. It was suggested that the mycostatic factor produced in the soil as a result of biological activity only extends down to a depth of 120–150 cm, whereas deeper layers in the profile possess an inhibitory factor which is non-biological in nature. The pattern of soil mycostasis was compared with those established for Nigerian and British soils and it was concluded that the pattern in Malayan soils resembled more closely that from Britain.