Down syndrome is a genetic disorder which is represented by a variety of deficits in all linguistic domains including phonology. Previous research, mainly conducted in the English language, has documented phonological deficits in early childhood in Down syndrome. Given the paucity of research in the area of phonology in the Greek language, the aim of the present study was to evaluate the phonological skills of children with Down syndrome (N = 45) in the Greek language and compare them with those of age-matched and non-verbal age children with language impairment (N = 45). A test, standardized in the Greek language, was used for the above purpose which consisted of four subscales: articulation; phonemic analysis; phonemic completion; and phonemic distinction. The results showed that children with Down syndrome performed poorer on all four subscales than children with language impairment, and provided evidence for distinct difficulties in specific consonants and complex articulations inherent in the Greek language.