The aim of this study was to evaluate the fermentation characteristics and nutritive value of two interesting forage species (maralfalfa and tagasaste) ensiled with molasses and beet pulp as additives. Ensilability parameters and chemical composition were analysed in two different stages of growth in maralfalfa (flowering and vegetative growing) and two different branch diameters in tagasaste (branches > 5mm, branches ≤ 5mm). According to ensilability results, four combinations with additives (two for tagasaste and two for maralfalfa) were ensiled at laboratory scale microsilos, in order to evaluate fermentative and nutritive parameters in two different conservation periods (35d and 70d). Tagasaste showed high dry matter (DM) content and fermentability ratio (FR) but a very low sugar content (WSC). Maralfalfa showed poor initial ensiling characteristics, low DM and WSC and high BC (buffering capacity). Supplementing tagasaste with molasses improves the fermentative composition in mini-silos with adequate ammonia-N and lactic acid concentrations detected. Moreover, the addition of beet pulp and molasses to the ensiled maralfalfa allows achieving the pH value under 4 and NH3˗N content below 10%, with an interesting content of lactic acid improving the fermentation quality of silage.