Background: Executive functions (EF) impairments have long been observed in children and youths with autism spectrum disorders (ASD). Until very recently, little attention has been paid to examine EF profiles of adults with ASD. Given the importance of EF to cope with the demands of daily life and participate in society (e.g. maintaining an employment), this study reports on a preliminary investigation aimed at exploring planning skills and cognitive flexibility in a sample of adults with ASD and without intellectual disability. A secondary aim was to explore the contribution of both intellectual functioning and socio-demographic variables on efficiency of EF. Method: Twenty-nine autistic adults (age range 18-50) were assessed using the Tower of London (ToL) test and the Wisconsin Card Sorting Test (WCST). Intellectual functioning was assessed with the Wechsler Adult Intelligence Scale - IV. Results: From the evaluations emerged poor performances in sub-processes related to planning skills as assessed by ToL (number of Moves, Correct Reponses, and Execution time). In contrast, WCST performance did not result impaired in any of the indicators considered. Exploratory analyses revealed a strong relationship between the time needed to complete the planning tasks and visuo-spatial reasoning. Further, strong inverse associations were found between global intellectual functioning and chronological age in the WCST. Conclusions: The results of this study highlight mixed EF profiles in a sample of adults with ASD. Future investigations may build on the results of the present study to understand whether evaluating planning abilities of adults with ASD by means of measures that do not require a time-limit would yield different results compared to time-constrained assessment procedures.