Cognitive performance is essential for children's functioning and may also predict school readiness. The suitability of Western standardized assessments for cognitive performance among children from different cultures needs to be elaborated. This study referred to the existence of differences in cognitive performance between and within children from the middle-east--Israeli and Palestinian on the Loewenstein Occupational Therapy Cognitive Assessment (LOTCA), by elucidating cultural effects on the construct validity of the LOTCA using factor analysis. Participants included 101 Israeli and 125 Palestinian children from kindergarten, first and second grade who underwent the LOTCA. Factor analysis revealed four factors underlying items on the LOTCA, explaining the differences found between Israeli and Palestinian children in most of LOTCA subtests. Culture may affect the construct validity of the LOTCA and may explain the difference in performance between both cultural groups. LOTCA's validity as well as the validity of other instruments on which norms and decisions regarding the child's development and performance are made should be further evaluated among children from different cultural backgrounds. (Contains 3 tables.)