This prospective observational pilot study investigated the effect of individualized homeopathy on male infertility based on sperm count, hormone values and general health. Forty-five subfertile men were treated with single homeopathic remedies for an average of 10.3 months. The drugs were prescribed on the basis of the overall symptomatic situation. The variables 'sperm density', 'percentage of sperm with good progressive motility' and 'density of sperm with good propulsive motility' improved significantly, especially in cases of oligoasthenozoospermia. The general health of patients improved significantly. The following factors emerged as positive predictors of therapy success: alcohol consumption below 30 g/day, non-smoking, the presence of less than five dental amalgam fillings, no exposure to noxious substances at the workplace and no previous inflammatory genital diseases. The factors stress, age above 36, high coffee consumption and long duration of unwanted childlessness did not have a negative impact on therapy outcome in this study. The rate of improvement in sperm count through homeopathic therapy is comparable to the improvement achieved by conventional therapy, so that individualized-homeopathic treatment may be considered a useful alternative to conventional treatment of subfertile men. For further investigation, a randomised, therapy-controlled clinical study with parallel group design would be useful (homeopathic therapy vs conventional andrological therapy).