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Soil nematode communities in the 0-15 cm soil layer are used as indicators for describing the processes of fallow succession in the semi-arid zone of West Africa (Senegal). Abundance of plant feeding nematodes, non-plant feeding nematodes, plant parasite index (PPI), species richness and Shannon evenness of plant parasitic nematodes were measured at five stages of succession: fields, early (1-3 years), intermediate (8-10 years), old (18-20 years) fallows, and forest stage. These nematological indexes were analyzed simultaneously by multivariate analysis to show the indicative properties of nematode communities. Overall, changes in abundance of nematode groups, PPI and diversity, show continuous trends from early fallow to mature stages of the succession; these trends parallel theoretical trends in secondary succession. In addition, soil nematode parameters were meaningful and expressed interactions of various uncontrolled factors with successional processes, such as environmental conditions or cropping history. During the 3 years of the survey, the structure of nematode communities, described by index analysis, showed little temporal change and supported the use of nematodes as stable indicators. (C) 2000 Elsevier Science B.V. All rights reserved.