The aim of the present study was to develop an intervention program involving environmental enrichment and caregiver training to improve the language and cognitive development of infants and young children residing in institutional settings in Turkey. Results indicated that institutional care quality was significantly improved in the intervention institutions, but remained unchanged in the control institutions. Furthermore, while the cognitive and language developmental gap of the infant and toddlers in the control group increased, this gap declined slightly for the infants and children in the intervention group. For the preschool-age group, it seemed that the general development t scores of the children in the intervention group increased, but those of the control group children decreased. It can be concluded that the intervention program was effective in increasing the care quality in orphanages and had a positive effect on the language and cognitive development of infants and preschoolers.