OBJECTIVES: This study examined whether participation in a weight control program was also associated with improvements in clinical and functional outcomes. METHODS: A post hoc analysis was conducted using data from the Chinese subgroup (n=330) of a multicountry, 6-month, prospective, observational study of outpatients with schizophrenia who were initiated or switched to oral olanzapine. At study entry, and each month for 6 months, participants were assessed with the Clinical Global Impression of Severity (CGI-S), and measures of patient insight and functional status. Change in level of illness severity, response rate, and time to response (all per CGI-S),  impaired work activities and insight level  were compared  between two groups:  (1) 153 patients who participated in a weight control program at study entry or during the study (WCP), and; (2) 177 patients who did not participate in the weight control program at any time during the study (NWCP). Univariate comparisons were conducted using Fisher’s exact tests for categorical variables and ANOVA for continuous variables. Kaplan-Meier survival analysis was used to assess time to response. RESULTS: Participants had a mean age 29.0 years and 29.3 years, and  51.0% and 57.6% were female for WCP and NWCP, respectively.  Average initiated daily dose for olanzapine was 9.5 ± 5.4mg. Weight control program participants gained less weight than non-participants (LS means weight change: 3.9kg vs. 4.9kg, p=0.03) and showed statistically significant  better  clinical and functional outcomes:  greater improvement in illness severity  (-2.93 vs -2.06 p<0.001),  higher treatment response rates (94.1% vs 80.9% p<0.001),  shorter time to response (p<0.001), higher proportion of patients without  impaired work activities (p<0.001), and greater improvement in patients’ insight (p<0.001). CONCLUSIONS: Participation in a weight control program may not only lower the risk of clinically significant weight gain in olanzapine-treated patients, but may also be associated with additional clinical and functional benefits.