A mental rotation task with unfamiliar stimuli was presented to 5-year-old (n=36) and 8-year-old children (n=36). The stimuli contained either an intrinsic salient axis (S+) or no salient axis (S-). Results showed that both 5-year-old and 8-year-old children were able to perform the mental rotation task with the S+ stimulus. However, 5-year-old children had difficulties in performing the mental rotation task with the S- stimulus. These results suggest that there are limitations in mental rotation abilities of young children. The ability to encode and mentally rotate unfamiliar stimuli containing no salient axis seems to improve between the ages of 5 and 8.