This is the third in a series of "India Studies". It investigated within Piaget and Witkin's theories: (1) the relationships among cognitive performance and cognitive style and predictive possibilities; and (2) performance differences by sex, school, grade, and income. The Sample consisted of 92 boys and girls of ages 12-15 years studying in private and government schools in Delhi, India; 47 children in grades 5-7, and 45 in grades 8-10; and 28, 35, and 29 children in the three income levels respectively. Assessment measures were: Liquid Conservation, Islands, Goat-Lion, Hanoi Tower, Rabbits (Piagetian); Block Design (WISC-R); Paper Cutting, and Memory Design (Stanford-Binet); and Children's Embedded Figures Test. Data were analyzed by correlational analyses, varimax and oblique factor analyses, multiple regression, and two-way ANOVA: grade (2)Xincome (3). Cognitive style correlated significantly with cognitive performance and proved to be a good predictor. Factor analysis showed a common underlying construct in spite of different theoretical formulations. Developmental differences by grade, and performance differences by income levels, sex and school type were noted. These findings supported those of earlier research and demonstrated the applicability of Piaget and Witkin's theories for a non-Western sample.