A high frequency of sexual dysfunction occurs in treated and untreated patients with schizophrenia. Unfortunately, no effective therapy for this problem is currently available. We present a case of a 26-year-old patient with paranoid schizophrenia, who suffered from lack of desire and erection, and was successfully treated with sildenafil citrate (Viagra). This case illustrates the complex character of sexual dysfunction in male schizophrenia patients.