Data from this in vivo albino rabbit study suggest that miconazole nitrate may penetrate the ocular compartments better than either natamycin or amphotericin B after intravenous, subconjunctival, or topical administration. The concentrations of miconazole in cornea and in aqueous humor after either topical or subconjunctival administration were very high, and a further threefold increase in the levels was seen if the corneal epithelium had been removed prior to drug therapy. Miconazole was found in the vitreous in some animals after subconjunctival injections of the drug. Intravenous administration produced high concentrations of miconazole in the aqueous humor, which rapidly fell over eight hours. No signs of toxicity or adverse reactions were found in these short-term experiments. Miconazole may be a useful addition in our methods of treating keratomycosis and oculomycosis.