The variation in abundance, richness, diversity, dominance and composition of the Orthoptera communities was studied along an altitudinal gradient, between 2000 and 3000 m, in an Andean forest at “Santuario de Flora y Fauna Guanenta - Alto Rio Fonce” (Santander, Colombia), from January to October of 2004. Surveys were conducted at five places every 250 m in altitude (located at 2000 m, 2250 m, 2500 m, 2750 m and 3000 m). The methods by study area included four quadrants (50 m x 5m each) for manual sampling. The general sampling was efficient (98.8 % ACE - 82.2 % Jackknife 1). The correspondence analysis and the similarity coefficients defined two different groups of communities (2000 m – 2250 m and 2750 m - 3000 m) due possible to the structural differences across the vegetation on altitudinal gradient. Species richness, as well as diversity, decreased gradually with increasing altitude, due to the reduced plant resource at high elevations. There was a positive correlation between altitude and dominance of Orthoptera species by the high proportion of the generalist species, probably by the best tolerance to adverse conditions. Not evident association between elevation and species abundance was observed. Regression models by Orthoptera richness, diversity and dominance are showed.