Forage cactus is an important resource for feeding domestic ruminants in semiarid regions and has been analyzed from a nutritional point of view, however it is necessary to know the nutritional quality of cladodes in function of the plant development stages. This study was conducted for evaluate the chemical-bromatological composition of the species Opuntia atropes Rose (genotype F-08) at different phenological stages. Cladodes were collected from five plants in three stages: young (cladodes expanding, with fragile structure and located at the distal or lateral extremities of the plant), intermediate (cladodes of rigid structure, located in the median part of the plant) and mature (cladodes fully expanded, rigid structure and located just above the base). There was no difference (P > 0.05) between phenological stages cladode in the concentrations of the dry matter (DM), organic matter, ether extract, mineral matter and non-fiber carbohydrates. The lower concentration of crude protein was observed in mature cladodes (56.06 g/kg DM) compared to young (67.28 g/kg DM). Neutral detergent fiber and acid detergent fiber concentrations were higher in the mature stage (357.63 and 213.23 g/kg DM, respectively). With cladode development, the concentration of total carbohydrates increased from 721.94 g/kg DM (young cladode) to 763.35 g/kg DM (mature cladode). The genotype of O. atropes has nutritional quality and these results can be useful to select cladodes with superior characteristics and to optimize their use in feeding different categories of ruminants.