Northeast Brazil has a large proportion of tropical semi-arid grasslands, with the Caatinga Biome as the predominant native vegetation, including many endemic legume species. Among these, Macroptilium species have an important role in the diet of ruminants. This study aimed to identify edaphoclimatic characteristics influencing the occurrence of Macroptilium species in Pernambuco's semi-arid grasslands. Macroptilium germplasm and soil were collected from eight soil types at 299 sites in 11 municipalities of Pernambuco. Edaphoclimatic data were recorded, and soil granulometric and chemical analyses were performed. A decision tree was established to understand the occurrence of Macroptilium species. The municipalities of Sert & acirc;nia, Parnamirim and Floresta presented the highest occurrence of Macroptilium, with Macroptilium lathyroides (L.) Urb being predominant (50%), followed by M. martii Benth (30%) and other species (20%). The occurrence of this genus was predicted by the edaphoclimatic variables (average temperature, annual precipitation, soil texture, and soil type). The decision tree showed that the occurrence tends to be greater in less dry habitats formed by well-drained soils with a low clay content. Understanding the edaphoclimatic conditions that influence the occurrence of Macroptilium is essential for selecting conservation sites and informing breeding programs to improve forage performance in semi-arid environments.