This review compares the tolerability profiles of the three currently available nonsteroidal antiandrogens, flutamide, bicalutamide and nilutamide. Pharmacological effects associated with blockade of the androgen receptor are frequent with all three drugs. Gynecomastia and breast pain are seen more frequently during antiandrogen monotherapy than during combination with medical or surgical castration or castration alone, and the reverse is true for hot flashes, which are a side effect of castration. Gastrointestinal symptoms are also common to all three drugs, but diarrhea occurs more frequently in flutamide studies than in bicalutamide or nilutamide studies. Hepatotoxicity has been seen with all three antiandrogens, but acute, reversible hepatitis and fatal fulminant hepatitis have also been reported with both nilutamide and flutamide. All three drugs have been associated with asymptomatic elevations in aminotransferases and may reduce hemoglobin levels. Adverse events that have been reported with nilutamide include interstitial pneumonitis, delayed adaptation to darkness after exposure to bright light and alcohol intolerance. To date, bicalutamide appears to have some advantage over flutamide and nilutamide in terms of tolerability.