The purpose of this study was twofold: (1) to investigate the appropriateness of Piagetian tasks for a comparative assessment of the cognitive development of rural and semi-urban Senegalese youth; and (2) to determine relationships among selected social and environmental factors affecting Senegalese youth. Fifty semi-urban and 50 rural area Senegalese children (64 males and 36 females) ranging in age from 6 to 15 years were individually administered five conservation tasks involving number, substance, and weight. Subjects' intelligence was assessed with the Goodenough Draw-A-Man Test (Harris, 1963) and by the Sills Electric Analog Test. Information relating to the children's family and living situation, and the effect of nutrition on their development was obtained through an interview and by measuring height, weight, and arm size of the children. Results indicated that maturation variables (years in school, height, intelligence, weight and arm size) were significantly related to all measures of conservation. However, when age was partialled out of these variables, none of them were found to be correlated with any measures of conservation. Social variables such as family size, number of wives of the father and number of rooms in the child's home were also found to be related to conservation. It was concluded that these results lend further support for the appropriateness of Piagetian tasks for a comparative assessment of the cognitive development of rural and semi-urban Senegalese youth. (Author/MP)