BALB/c mice infected with a high virulent strain of Trypanosoma brucei gambiense IL3707 were treated intraperitoneally (ip) with either Melarsoprol (Mel-B) or PSG(+) buffer as controls. The mice were subsequently monitored regularly for parasites by direct microscopic examination of their tail blood or buffy coat and by polymerase chain reaction (PCR). Mel-B was found to be an effective drug for treatment against T.b. gambiense because at the end of the first treatment schedule, all treated mice were negative for parasites even by PCR, while all the control animals were positive. Three of the five Mel-B treated mice, while parasitologically negative, were PCR positive between 53 and 80 days post infection (DPI), indicating that they still harbored an infection. All treated mice were subsequently negative for parasites even by PCR at 88 DPI. A combination of conventional microscopic examination and PCR offers a good prediction of cure following treatment of trypanosomosis.