Surveys were carried out in the last remaining forests of southwest Tanzania's Ufipa Plateau to determine the presence, distribution and abundance of the red colobus Procolobus rufomitratus tephrosceles. In 2002, we investigated the Chala and Misheta forests. Chala was in poor condition, and no primates were seen, although it is not known if red colobus ever existed there. There was almost no natural forest remaining in Misheta, and we consider its red colobus population to be now extinct. Analysis of satellite imagery revealed that the Nsangu Forest no longer exists, and we assume its population is also now extinct. In August 2006, a previously undocumented red colobus population was discovered in Mbuzi, 55 km north of the only other extant population in Mbizi. Complete count censuses were performed in Mbuzi and Mbizi. A total of 1,217 individuals were recorded in Mbizi and 137 individuals in Mbuzi, giving a combined total of 1,354 individual Ufipa red colobus. Mean group size in Mbizi was 40.56 (n = 30; SD = 6.57; range 30–56) and in Mbuzi was 34.25 (n = 4; SD = 13.07; range 24–50). The Mbuzi subpopulation may no longer be viable and the subpopulation of Mbizi may be declining. Both forests are heavily degraded and require urgent conservation attention.