Objective — to study a relationship between plasma levels of antipsychotics (AP) and severity of side-effects (SE) during the treatment of inpatients with exacerbation of schizophrenia. Material and methods. The study included 39 patients treated with risperidone, haloperidol, zuclopenthixol, clozapine, aripiprazole or olanzapine as monotherapy or in combination of two AP. Blood sampling to measure the AP plasma level was performed twice (at 7—10 and 26—30 day from start of treatment), the levels of prolactin and glucose were determined once (at 26—30 day from start of treatment). Patients were assessed by psychometric scales PANSS and NSA and the side-effects scale UKU. Results. The increased concentration of AP was noted in 33% of the patients. The high concentration of AP was significantly associated with akathisia and hyperkinesia (by UKU scale), NSA retardation factor and hyperprolactinemia. Patients with severe hyperprolactinemia were twice as likely to have a clinically significant depression. Increased blood glucose levels were observed in 18% of the patients, there was no significant association with AP plasma levels. Mental SE were most prominent, with a drift towards the neurological SE in the group with higher AP plasma levels. Chlorpromazine equivalent didn’t significantly differ in the groups with normal, high and low AP concentrations. Conclusion. Elevated AP plasma levels, which were associated with some clinically significant SE and some negative symptoms, were found in most patients. In this regard, therapeutic drug monitoring is a promising method for the individualization of schizophrenia exacerbation treatment in routine clinical practice.