Seeding legumes in autumn would allow increasing and regulating yield, but requires to improve the level of frost tolerance in varieties, which motivates the interest in deciphering the genetic determinism of this trait. In pea (Pisum sativum L.), this character is controlled by a few quantitative trait loci (QTL) that were identified by the analysis of RIL populations derived from contrasted genotypes, such as Champagne (Ch, tolerant) x Térèse (Té, sensitive), or by association analysis [1,2,3]. We study a QTL located on the pea linkage group 6 (WFD6.1), which accounts for a large part of frost tolerance variability, making it a choice target for selection purposes. In order to get access to the QTL structure in Ch and Té, we exploited pea and Medicago truncatula (Mt) genomic resources [4,5]. Thus, we keyed out within WFD6.1 genes encoding CBF-like transcription factors (TFs) present in a Mt orthologous QTL and known to be involved in frost tolerance in various plant species. We built BAC libraries for Ch and Té, screened them with probes designed in CBF genes across WFD6.1, then sequenced and assembled positive clones. The region turns out to be 33 % larger in Té than in Ch. Besides, a gene annotation, performed using the PlantTFcat database, shows that TFs are distributed across three loci in Ch and two in Té, only one of them being common. We are currently refining this analysis, aiming at extensively describing polymorphism across WFD6.1, especially in CBF genes, in order to set up a catalogue of their diversity. We present here preliminary results from this approach.