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Resistance to bean common mosaic virus (BCMV) strain NY15 (Zaumeyer) and bean common mosaic necrosis virus (BCMNV) strain NL-3 (Drijfhout) was assessed in 98 F5:6 recombinant inbred lines (RILs) derived from a cross between pinto bean (Phaseolus vulgaris L.) cultivars `Olathe' and `Sierra'. `Olathe' has bc-u and bc-12 whereas `Sierra' has no known resistance genes. The differentiation of resistant and susceptible lines was based on visual symptoms, virus titer, and top dry weight. Forty-seven RILs were moderately resistant to NL-3, while 51 RILs were susceptible. This segregation fits a 1 susceptible: 1 resistant ratio characteristic of a single gene. Sixty-nine RILs were susceptible to NY15, while 29 RILs were resistant, which fits a 3 susceptible: 1 resistant ratio characteristic of a two-gene model. Moderate resistance to NL-3 was conferred by bc-12 with or without bc-u present. Bulked segregant and two point linkage analysis identified randomly amplified polymorphic DNA (RAPD) markers linked in coupling to the Bc-1 and Bc-u alleles. The OH141100 RAPD marker was 4.5 cM from the Bc-1 locus. The OC161000 RAPD marker was linked at a distance of 10.9 cM from the Bc-u locus. Multipoint analysis, using segregation data for bc-12 , bc-u, and the two markers, estimated the distance between the Bc-1 and Bc-u loci as 22.8 cM.