The FecB mutation in the BMPR1B gene and the G6, G7 and G8 mutations in the GDF9 gene have been documented in Booroola Merino sheep breeds. These mutations have all been identified in several ovine breeds, such as Belclare, Cambridge. Blackbelly hairy sheep breed, which is well adapted to tropical climates due to its African origin, have 2 to 3 lambs per litter, corresponding to a high prolificacy for a tropical breed. The objective of this investigation was to identify mutations in the cDNA of the BMPR1B and GDF9 genes of 20 Blackbelly ewes selected for their prolificacy (two or more lambs by birth). The results of this study indicate the absence of mutations in these genes from the Blackbelly breed. However, it is important to analyze the 3' end region of the cDNA of these genes to rule out the presence or absence of other mutations related to prolificacy.