Journal ArticleThis study sought to assess cognitive development of preschoolers in the selected pre-primary schools in Morogoro Municipality as a requisite for successful primary education. Cognitive development focuses on information processing, such as decision-making, attention, memory, language abilities, learning, and perceptional skills. The study involved 213 preschoolers from 10 randomly selected preschools in Morogoro Municipality. The study employed International Development and Early Learning Assessment tool (IDELA) in data collection. Both Kiswahili and English versions of IDELA was used in assessing cognitive development of children. The study found that Morogoro Municipality preschoolers have excellent development in all spheres of cognitive development. For example, preschoolers had the mean of 92 in early numeracy, 80% in early literacy and a mean of 90% in executing executive functions. Furthermore, statistically significant difference in cognitive development of pre-schoolers was found based on their age (at p <0.00), sex (p<0.00 for early literacy. Based on the type of school, the study found p<0.00 for numeracy, p= 0.02 for executive function and p ≤ 0.00 for early literacy. The study recommend that parents should be encouraged to enroll their children in preschool centers.