In 2012 and 2013 a study was conducted to determine the area of distribution and conservation status of Callicehus oenanthe "mono tocon" in the San Martín region. In 2007, the Mono Tocon Project association conducted a similar study that found that C. oenanthe not only lives in the High May, but also in the Low May and in the Central Huallaga. This advance infonnation has been compared with the results obtained during this study. There visited a total of 171 localities in five hydrographic basins of the San Martín region: High May, Under May, Under Huallaga, Huallaga Central and High Huallaga. In each locality infonnation was collected from interviews, vocalizations and observations. In addition to infonnation on agricultura! crops and the threats facing C. oenanthe within its area of distribution. The obtained results show that C. oenanthe he meets in the High May, Under May and Huall...