Schizophrenia is one of the major problem of the modern psychiatry. Due to its chronic nature, it requires continuous treatment with antipsychotics. Weight gain is one of the major drawbacks associated with the pharmacological treatment of schizophrenia. Aripiprazole is one of the atypical antipsychotics, with relatively good metabolic profile. There are very few published cases of aripiprazole-induced weight gain. We present a case of significant (50 kg) weight gain during 4-year treatment with aripiprazole in a 21-year-old Caucasian man with a diagnosis of paranoid schizophrenia. The mechanism underlying aripiprazole-induced weight gain may be associated with its potent binding to serotonin 5-HT2C receptor. This case confirms how significant is to monitor patients taking antipsychotics.