In the past many authors have supported the idea that individuals with Williams syndrome (WS) were characterized by a unique cognitive profile, with severe difficulties in visuo-spatial abilities and relatively spared linguistic abilities. Recent studies have not confirmed this cognitive pattern and have described a more complex profile which shows some modifications during development. According to this perspective the present study investigates cognitive abilities of an homogeneous sample of children with WS, within a restricted chronological and mental age range. Performances of WS children on a general Intelligence scales (WISC-R or WPPSI), on a naming task (BNT), and on a visual motor test (VMI) were compared with those of two control groups of typically developing children, one matched for chronological age and one for mental age. Results show that children with WS exhibit linguistic and visuo-spatial abilities according to their mental age and interesting peculiarities in the processes underlying various cognitive functions.