This paper aimed to describe the design and development of the social domain of the Preschool Developmental Assessment Scale (PDAS), which would be used for assessment of preschool children with different developmental disabilities. The original version of the social domain consisted of 30 items. Children were asked questions about their social development such as their relationship with others, understanding of social norms and rules, empathy and perspective taking. The test was administered to 324 children, including 240 children from preschools and 84 children with developmental disabilities. Rasch analysis was conducted, and all except one item were within the acceptable range of infit statistics. The revised 29-item version could well differentiate between children with typical development and children with developmental disabilities. It could also differentiate between children from different age groups. The revised version was estimated to take around 15 min to administer. The social domain of the PDAS was found to be a direct, quick yet reliable assessment tool for assessing the social development of preschool children. (Contains 1 figure and 2 tables.)