Several experimental trypanocidal compounds, 6-amidino-2-(4-amidinophenyl)indole dilactate (DAPI), DL-alpha-difluoromethylornithine (DFMO), 2-(dimethylamino)-4'-[(1-methyl-2-nitroimidazole-5-yl) methoxy] aceto-anilide (Ro 15-0216), sinefungin, and triacetylbenzene-tris(guanylhydrazone)trimethanesulfonate hydrate (TBG-MS) were tested to evaluate their ability to cure mouse infections with a multiple drug-resistant Trypanosoma brucei brucei stock (CP 547). This stock proved to be drug-resistant against diminazene aceturate, homidium chloride, isometamidium, quinapyramine sulfate, Mel B, and pentamidine isethionate but fully sensitive to suramin. Compared with the sensitive stock CP 462, the drug-resistant stock CP 547 was completely resistant to 16-fold the curative dose of sinefungin and partially resistant to 4-fold the curative dose of DAPI and to 13-fold the curative dose of TBG-MS, a dose that killed 25% of the animals due to its toxicity. Ro 15-0216 cured all mice when 18 times the usual curative dose level was given. DFMO was equally effective against both stocks.