Objectives Atypical antipsychotics show better treatment efficacy, safety and tolerability than typical antipsychotics. Among the adverse events observed during treatment with antipsychotics, extrapyramidal syndrome (EPS) and negative symptoms has been greatly reduced. But still, weight gain is receiving growing attention. The aim of this study was to investigate the association between therapeutic response to atypical antipsychotics and weight gain in admission status. Methods The study was conducted for Korean inpatients with schizophrenia in a university hospital in Seoul, between Jan 2006 and Dec 2010. Data was collected by reviewing the medical record of 39 consecutively hospitalized patients with Schizophrenia (DSM-IV) at a university hospital. Positive and Negative Symptom Scale (PANSS), Body Mass Index (BMI) and body weights were measured. Results No significant difference was observed for sex, age, illness onset age, family history of schizophrenia, numbers of hospitalization before treatment, educational years, marriage status, occupational status and subtype of schizophrenia between weight gainers and non-weight gainers. Regarding treatment response to atypical antipsychotics, weight gainers show significantly more PANSS decrease than non-weight gainers during admission period. Conclusions Our findings suggest that it appears to be more likely to respond to atypical antipsychotics in weight gainers than non-weight gainers (that weght gainers appear to be more likely to respond to atypical antipsychotics than non-weight gainers). These results show that the antipsychotic-induced body weight gain is associated with therapeutic response of antipsychotics in Korean inpatients with schizophrenia.