Drying of cassava chips (a major staple food in many African countries) under natural conditions constitutes a major problem in a humid climate. A study was conducted in Ibadan in the humid zone of Nigeria to assess the rare of drying of cassava under different natural conditions. Samples were collected at regular intervals and moisture content determined in the laboratory. The sunshine hours, daytime temperature and relative humidify were recorded during collections of samples, in order to study their influence on drying. There were no significant variations in the drying patterns of chips dried at about equal weight per unit area. The average ambient equilibrium moisture content was about 16% (wet basis) after about 70 h of sunshine. However; the thickness of the layer of chips had significant effects on the nature and pattern of drying. The use of locally constructed solar dryers appeared to be the most promising. Copyright (C) 1996 Elsevier Science Ltd.