A case of chromomycosis from Comoro Islands was first treated without success with high doses of oral amphotericin B (3 g per day). Treatment with itraconazole (400 mg per day) was also unsuccessful. Then, in vitro tests were done to study the susceptibility of this Fonsecaea pedrosoi strain to antifungal drugs. It was resistant to itraconazole, sensitive to 5-fluorocytosine, and the combination of 5-fluorocytosine with amphotericin B was synergistic. The patient was then treated with this last combination of drugs, which seemed to be effective. The patient stopped this treatment after six months, and relapse occurred two years later. The best therapeutic strategy in cases of chromomycosis seems to be a combination of two drugs chosen according to the results of prior antifungal susceptibility testing.