We developed and characterized 36 polymorphic microsatellite markers for the oyster mushroom (Pleurotus ostreatus). In total, 169 alleles were identified with an average of 4.7 alleles per locus. Values for observed ($H_o$) and expected ($H_E$) heterozygosities ranged from 0.027 to 0.946 and from 0.027 to 0.810, respectively. Nineteen loci deviated from Hardy-Weinberg equilibrium. Significant (P<0.05) excess heterozygosity was observed at nine loci. Linkage disequilibrium (LD) was significant (P<0.05) between pairs of locus alleles. Cluster analysis revealed that five species of genus Pleurotus made a distinct group, and the individual cultivars were grouped into major five groups from G-1 to G-5. The diverse cultivars of P. ostreatus were discriminated and the other four species revealed a different section in the UPGMA tree. These microsatellite markers proved to be very useful tools for genetic studies, including assessment of the diversity and population structure of P. ostreatus.