A 29-year-old man, who met DSM-IV criteria for schizophrenia, had never experienced ejaculatory problems. He had his first psychotic episode, including delusions, auditory hallucinations, and ideas of reference at age 25, and was successfully treated with risperidone, 2 mg/day, without any major adverse effects. At age 28, he was admitted to a psychiatric inpatient ward after a second psychotic exacerbation of the disorder. At that time, the administration of olanzapine and leveomepromazine was initiated at a dose of 5 mg/day and 25 mg/day, respectively, and, 3 weeks later, they were increased to 20 mg/day and 100 mg/day, respectively. He was discharged home 2 months after starting levomepromazine treatment and then reported a complete failure to emit semen but a normal desire, erection, and sense of orgasm. Medications were olanzapine and levomepromazine at 20 mg/day and 150 mg/day, respectively. He was referred to the urology department, and sperm presence in the post-ejaculatory urine sample confirmed a diagnosis of retrograde ejaculation. A reduction of levomepromazine dose from 150 mg/day to 25 mg/day was associated with restoration of anterograde ejaculation, and the patient has subsequently been maintained on 20 mg/day of olanzapine without any ejaculatory problems.