Guassa area has a total area of 111km2. Before the present study, norncomprehensive census of geladas in the Guassa area had been carried out. Thernmethod used to census geladas living at Guassa was a total count. In addition,rnthe age-sex structure of the geladas, the number of one male units (OMUs) perrnband, the size and composition of OMU and all male group (AMG), in therngelada population were investigated. A total of 1506 and 1543 geladas wererncounted during wet and dry seasons respectively. The adult sex ratio for bothrnwet and dry seasons was 1:2.8 in favour of females. When the bachelors werernexcluded from the analysis, there were 4.1 adult females for each adult male.rnThe ratio of sub adults, young, and infants to adults was 1:1.2. The ratio ofrnadult females to infants was 1:2.5. With regard to the number of OMUs perrnband, there were 18.0 and 18.4 during wet and dry seasons respectively. Thernmean OMU size during the wet season was 12.15 of which 4.13 were adultrnfemales, 0.66 were sub-adult males,1.92 sub adult females, 2.64 young and 1.70rninfants. During the dry season, the mean OMU size was 1166 which wasrncomposed of 4.12 adult females, 0.59 sub-adult males, 1.93 sub adult females,rn2.50 young and 1.46 infants. The mean AMG size during the wet season wasrn6.41. During the dry season, the mean size of AMG was 6.23.. The ratio ofrnAMGs to OMUs was 1:10.0 and 1: 10.5 during the wet and dry seasonsrnrespectively. Generally, there was no significant difference among the totalrnpopulation number, age-sex categories, and the number of OMUs per band, thernsize and composition of OMU and the size of AMG during dry and wet season.rnThough the actual size of the gelada population is significantly lower than thernexpected, based on previous unpublished report of Fashing and Nguyen, 2007,rnthe overall condition of the current population does not appear to be inrnjeopardy. But there are many conservation threats such as habitat degradation,rnintroduction of non-native plant species and harvesting/gathering, which arerndirectly or indirectly related with the growth of population in the area that willrnthreat the future survival of the species. Key words/phrases: AMG, Band, Conservation threats, Gelada baboon,rnGuassa area, OMU, Population census and t0tal count