Loss of antipsychotic efficacy (tachyphylaxis), possibly linked to an increase in D2 receptor number and sensitivity, is a significant impediment to treatment in chronic schizophrenia patients. Animal studies, however, suggest that aripiprazole may be free from tachyphylaxis. The aim of the present study was to investigate this hypothesis. In this preliminary study, aripiprazole-treated patients were retrospectively investigated for the presence or absence of tachyphylaxis. Clinical Global Impression-Improvement (CGI-I) scores did not significantly change and there was no significant association of CGI scores with fixed dose duration. This suggests that aripiprazole may be free from tachyphylaxis.