Abstract Background Traumatic brain injury (TBI) in children is a significant health burden worldwide. Children aged 0 to 4 years have the highest incidence of TBI among the non-elderly. These children suffer from long term neurological deficits that compromise their quality of life and daily living activities. Objective To determine the developmental outcomes of infants and children with TBI. Subjects and Methods A prospective descriptive study on infants and children with TBI was conducted. Developmental outcomes by Age and Stage Questionnaire 3rd edition (ASQ-3) was assessed twice; once at hospital discharge and another time 3 months later. Further, Bayley scales of infants and toddlers’ development III was assessed only once in the second visit. Results at discharge and follow up were compared and correlated. Results Eighty -five patients were included in the study with 63.5% were males and the median age was 24(12-34) months, range (1- 42 months). There were statistically significant difference between ASQ-3 at discharge and follow up which was higher at follow up than at discharge indicating better developmental outcomes(P < 0.001 for all aspects). Comparison between ASQ-3 (problem solving) and Bayley Scale (cognitive) at follow up shows that there was no statistically significant difference between them with kappa agreement and 95% CI of 0.527 (0.218–0.837). Also, comparison between ASQ-3 (motor) at follow-up and Bayley Scale (motor)at follow up shows that there was no statistically significant difference between them with kappa agreement and 95% CI of 0.285 (0.001 - 0.569). Also, comparison between ASQ-3 (communication) and Bayley Scale (language) at follow up shows that there was no statistically significant difference between them with kappa agreement and 95% CI 0.501 (0.235 - 0.766). this means that both tests were comparable Conclusions ASQ-3 can be used as a screening tool for infants and children after TBI before referral to Bayley scale. Developmental milestones improved at follow up in most infants and children after TBI.