Ascochyta blight is the most common disease of economic importance in peas (Pisum sativum L.) in North Dakota. Selection based on molecular markers would greatly facilitate identification of resistant varieties. A mapping population comprised of 394 F7-derived recombinant inbred line (RILs) and derived from the cross `Lifter'/'Radley' was developed to study resistance to Ascochyta blight. A genetic map was developed based on 179 loci including SSR, RAPD, and CAPS markers, distributed on seven linkage groups. Phenotyping for reaction to Ascochyta blight was carried out under greenhouse and field conditions. Five replicate plants were scored using a 0 to 5 scale, where 0 = no disease and 5 = plant death. Forty-three lines showed a high level of resistance and QTL analysis identified ten DNA markers associated with Ascochyta blight resistance genes. This genetic map will provide additional insight to localize disease resistance genes/QTLs and aid development of resistant varieties.