The study was conducted to evaluate fodder oat genotypes for yield and yield attributes for four years (2007/08-2010/11) under four locations of Bale highland. Eleven fodder oats genotypes were evaluated in Randomized Complete Block Design (RCBD) with three replications with the objective to evaluate oat genotypes for yield and yield attributes and to test their adaptation performance in the highlands of Bale. It was observed that, most of the yield and yield related parameters were significantly different among the tested genotypes. The results revealed that genotype 79AB384 performed better for most important yield parameters. This genotype produced the maximum forage dry matter (DM) yield (10.3 t/ha) and seed yield (2870 kg/ha) showing the yield advantage of 19.4 and 24.5 % over the checks respectively. The analysis of variance for DM yield showed that 48% of the total sum of square was attributed to environmental effect. The genotypic and GEI (Genotype*Environment*Interaction) effect explained 4.7 and 18.7% respectively. The stability test also indicated that genotype 79AB384, CVmn79988385 and CS2(1563CR) were found more stable in dry matter yield and well adapted to the tested environments. Hence, genotypes 79AB384, CVmn79988385 and CS2 (1563CR) proved to be better performances among eleven genotypes tested under Bale highland conditions. Furthermore, similar breeding/selection activities on fodder oats and other forage varieties should be carried out to evaluate and develop varieties/ genotypes with good yield performance and widely adapted to different agro-ecologies of our country. Keywords: Fodder oats, Avena sativa, herbage yield, Bale highlan