In Sunflower hybrids are obtained by using the cytoplasmic male sterility/fertility restoration system, which is due to a nuclear-cytoplasmic incompatibility. Hybrid breeding is based on the cytoplasmic male sterility, PET1. Male fertility can be restored by the nuclear restorer gene Rf1. The objective of this study was to use a map-based cloning strategy to isolate the Rf1 gene. Seventy-one BAC-clones were identified. Twenty-seven BAC-ends were isolated. Contigs were formed, each representing a unique genomic region. The two BAC libraries used have a too low coverage in the region of Rf1 gene.