Water and soil samples collected from the mouth to origin of the Savannah and Tombigbee Rivers were treated for enumeration of organisms of the Mycobacterium avium, M. intracellulare, and M. scrofulaceum (MAIS) complex. Their numbers in soil and water were compared to physiochemical characteristics of these samples. Further, the number of MAIS organisms recovered from acidified and alkalinized soil samples, measurement of possible movement of soilborne MAIS organism into water and the numbers in soil and sediment at one location in the James River were investigated. Most MAIS organisms in soil (95%) could not be recovered because of irreversible binding. Appreciable numbers of MAIS organisms from soil were recovered along the entire length of both rivers, while high numbers in water were recovered toward the mouth and from turbid water samples. However the numbers in soil were much greater than those in water and numbers in sediment were greater than those in soil. The number recovered from soil was highest in acidic samples and in those with high organic matter content. High soil conductivity was associated with high recovery of MAIS organisms in the Tombigbee but not the Savannah River. The recovery of MAIS organisms from acidic soil samples could not be decreased by increasing soil pH, nor recovery from basic or neutral soils increased by acidification. Waterborne MAIS organisms were recovered from soil in a laboratory simulation of percolation of water through soil. / M.S.