Winter hardiness is an important limitation to winter oat (Avena byzantina and A. sativa) production in much of North America, but field evaluation of winter hardiness is difficult.  Identification of quantitative trait loci (QTL) for winter hardiness component traits (WHCT) should increase the ability of breeders to select for winter hardy oat lines. The objective of the study was to identify QTL associated with  the WHCT: winter field survival, crown freeze tolerance, vernalization response, photoperiod response, and heading date, in a winter oat recombinant inbred line (RIL) population of 139 RIL derived from a cross between winter hardy ‘Norline’ and winter tender ‘Fulghum’.  Selected RFLP probes and SSR markers were mapped and QTL were identified.  Three QTL for winter field survival, five QTL for crown freeze tolerance, three QTL for heading date, and two QTL for vernalization response were identified accounting for 64%, 75%, 40% and 29% of phenotypic variation, respectively.  No QTL for photoperiod response were identified.  These QTL may assist breeders in improving oat winter hardiness.