Periodic evaluation of the natural resources of a protected area is necessary to assess the status and effectiveness of conservation efforts made for this purpose. In this context, the management of Pendjari National Park has been undertaking a series of censuses (aerial and pedestrian) of wildlife in the Pendjari Biosphere Reserve (RBP) since 2000. Thus, to complete this available database on the periodic status of wildlife, a count based on the strip-transect count aerial census method was carried out in April 2006. In total, 18 transects with a total length of 972 km and a width of 250 m x 2 were covered during this operation. The area covered therefore corresponds to 10.15% of the area of this reserve. The operation took place with a CESSNA 182 high-wing aircraft flying at an average altitude of 120 m and at an average speed of 185 km/h. Therefore, for the entire reserve and for each of the components, an aggregative distribution according to water points is noted. The evolution of numbers and densities shows a sharp fluctuation from year to year with increasing minima except in the case of koba between 2004 and 2006. On the other hand, densities evolved in the RBP and the PNP but fell between 2004 and 2006 in the ZCP. The drop in koba numbers in the study region may be due to illegal harvesting by poachers or to some migration to other nearby protected areas in Burkina Faso and W Benin (to be studied)