Weonhyeong is one of important commercial strains. It has good characteristics of bundle formation, grey colored pilei and high productivity. We previously reported grouping of 70 strains of Pleurotus ostreatus in which one group contained 35 strains including Weonhyeong. Four strains in that group showed same profiles implicating no variety distinction for mushroom cultivation. Now we developed a specific marker for identification of Weonhyeong. Sequence Characterized Amplified Region (SCAR) marker was developed from the RAPD amplicon. SCAR marker ‘S-OPO5’ produced only one band specific to 2183, 2240, 2595 and 2725 strains showing similar banding patterns to Weonhyeong in RAPD-PCR results. The sequence of ‘S-OPO5’ marker was unknown when compared with the data in the Genbank using BLASTN. BLASTX results indicated that the marker showed significant alignment with the protein sequences in Tricholoma bakamatsutake reverse transcriptase. The results indicate that this new SCAR marker ('S-OPO5') will be valuable to distinguish the Weonhyeong similar strains from Pleurotus spp.