Pyoderma gangrenosum, cystic acne, and aseptic arthritis are clinically distinct disorders within the broad class of inflammatory diseases. Although this triad of symptoms is rarely observed in a single patient, a three-generation kindred with autosomal-dominant transmission of these three disorders has been reported as “PAPA syndrome” (MIM 604416). We report mapping of a disease locus for familial pyoderma gangrenosum–acne–arthritis to the long arm of chromosome 15 (maximum two-point LOD score, 5.83; recombination fraction [θ] 0 at locus D15S206). Under the assumption of complete penetrance, haplotype analysis of recombination events defined a disease interval of 10 cM, between D15S1023 and D15S979. Successful identification of a single disease locus for this syndrome suggests that these clinically distinct disorders may share a genetic etiology. These data further indicate the role of genes outside the major histocompatibility locus in inflammatory disease.