Babati town was one of several areas in Tanzania that was flooded during the heavy rains in 1990. Lake Babati, situated to the south of the town, is a shallow fresh water lake rapidly responding to climatic fluctuations. The lake surged on April 6, 1990. The flood created a new outlet of the lake through the town centre. Street gutters were transformed into gullies and several buildings were destroyed. Analyses of climatic data, aerial photography and old records indicate that the floodings commenced in 1964 after a relatively long dry spell when the lake was reduced to about 1/4 of its present size. Subsequent floods occurred in 1979 and 1990 and can all be related to the building up of ground and surface water resources in the catchment after periods of increased rainfall amounts. The recent land use changes are discussed in relation to the natural causes of the floods.