Tropical pastures have been little explored for haylage, due to the lack of information on nutritional quality. This study aimed to evaluate the fermentation quality of different genotypes of forage grasses from tropical pastures in the form of haylage. Six genotypes of grasses were used to evaluate the fermentation characteristics, losses and presence of microorganisms in the in the haylage. The completely randomized design was used for all variables. Data were subjected to analysis of variance with all genotype’s means compared by the Scott Knott’s test at 5% probability. There was effect of interaction between form of material x genotype (P<0.01) on all variables of chemical composition evaluated in the in natura and haylage at the moment of haylage making, except for NDF and N-NH3 (P>0.05). The concentrations of O2 in the haylage after 60 days of storage were lower for the genotypes Xaraés and Tupã. The highest levels of acetic acid were observed in genotypes Xaraés, Planaltina and Tupã. The Planaltina genotype presented the highest DM loss in the process of production and storage of the haylage, averaging 8.2 ± 0.37%. The haylage of the species B. brizantha and M. maximus presented better nutritional characteristics.