Elephant grass (Pennisetum purpureum Schumacher) is a species of C4 perennial tropical grass native to the African grasslands. It has a vigorous growth and high biomass production, which is commonly used for feeding cattle in subtropical areas. It has low water and nutrient requirements, and therefore can make use of otherwise uncultivated lands. Currently it is evaluating the potential for production of second generation bioethanol. The biomass energy fitness can be assessed using the same parameters used for determining the nutritional value of forages, due to the similarity that both processes occur. The bioenergetic potential of the biomass of two varieties of elephant grass in the grounds of the FCA-UNLZ was studied. Var. Mott (dwarf) and Var. Panamá (High) were implanted in individual plots since 1996. These showed a great adaptation to the soil and climate of the Pampeana region for 20 years. DBCA was used with 3 replications. The experimental unit consisted of 2 rows of 4m×1m (density at harvest 10000 plants ha^-1) on which dry matter yield was determined (DMY, kg ha^-1), plant height (Height, m), proportion of leaf (Leaf, %). The manually harvest took place on 1 April 2016 (31.07 %DM average). The quality parameters were determinate on a fraction of stem+leaves of the middle section of the plant. Total solids content (B, °Brix) was determined in fresh. Later, the samples were dried to determine the content of dry matter (DM,%) and then were ground to 1 mm to evaluate the following variables quality laboratory: Neutral detergent fiber (NDF,%); Acid detergent fiber (ADF,%); Acid detergent lignin (ADL,%) and ash (Ash,%). Lignin (L,%) was calculated as LDA-C, cellulose (CEL,%) as FDA-CEL, and hemicellulose (HCEL,%) as FDN-FDA. In turn, the quality variables were evaluated in the leaf fraction and stem separately. The result of ANVA when comparing both varieties showed that only significant differences for variables Height (2.49m vs. 1.78m) and DMY (23543kg ha ^-1 vs. 6226 kg ha^-1) for Panamá. Both varieties had similar values for quality parameters. However, Mott had a trend to higher levels of bioenergy quality. When analyzing stem vs. leaves fraction, no significant differences were found between varieties. Leaves presented a lower content of L than stem, with no significant differences in the other variables analyzed. In conclusion, Panamá presented a better performance to be used as resource to produced biomass to bioenergy because of its greater DMY and similar quality.