Inheritance of resistance of the Indian melon line PI 124112 to several races of Sphaerotheca fuliginea and Erysiphe cichoracearum was studied. A set of homozygous recombinant inbred lines has been produced by single seed descent after a cross with the susceptible line Védrantais. Nine strains of powdery mildew were tested for powdery mildew resistance using a leaf disk assay and a whole plant test. Among the six strains of S. fuliginea tested, four different races were distinguished based on the reaction of nine different melon cultivars. The three strains of E. cichoracearum belong to the same race (race 1). Genotype PI 124112 was resistant to all the strains tested. Genetic analysis revealed that PI 124112 possessed four genes for resistance. One gene was able to control the races 1 and 2 of S. fuliginea, one gene controls the races 1, 2 and 4 and one gene controls the four races of S. fuliginea and also E. cichoracearum. One gene controls only E. cichoracearum (and not S. fuliginea). All these genes are linked in a cluster spanning 22 cM.