Schizophrenia is one of the most expensive illnesses. Antipsychotics are an essential component of the acute and preventative treatment of this illness, and long-term treatment is necessary to decrease the risk of psychotic relapse. The efficacy and tolerability of flupentixol was evaluated in a post-marketing surveillance study (PMS) in schizophrenic patients receiving long-term treatment in routine clinical practice. Psychiatrists in office practice treated patients for approximately 10 weeks, with a subsequent follow-up period of up to 18 months. We here report on the follow-up period in 128 patients. The benefit for schizophrenic patients increased with the treatment duration of flupentixol as documented by the Clinical Global Impression (CGI). Subjective quality of life improved during the first study period, and this remained stable in the follow-up period. No increase in body weight was observed during the study. The relapse rate was much lower than in other studies. Anticholinergic medication was necessary for 22.7% of the patients at any time. More than 70% of the psychiatrists involved evaluated the treatment as very good or good. The results of this study suggest that flupentixol is a potent and safe antipsychotic for the long-term treatment of schizophrenia in routine clinical practice.