Rice blast resistance genes are important for rice (Oryza sativa L.) improvement programs. DNA markers linked to resistance genes are a powerful tool to detect the presence of genes and are widely used in the selection of breeding materials through marker-assisted selection. This study was conducted to evaluate the detection ability of DNA markers for the rice blast resistance genes Pib and Pita in IRRI-bred rice varieties. Forty-two Indica-type varieties, which have been previously analyzed for the presence of Pib and Pita by conventional genetic analysis using a differential system involving standard blast isolates (Pyricularia oryzae Cavara) from the Philippines, were tested. To detect for the presence of Pib and Pita, previously reported PCR-based dominant markers were used. DNA fragments of Pib using the DNA marker Sub3-5 were amplified in 40 out of the 42 varieties examined. Additionally, DNA fragments of Pita using three gene specific markers were amplified in 27 or 28 varieties out of the 42 examined, depending on the marker used. The results of DNA marker analysis of 42 IRRI-bred rice varieties were largely consistent with those of previous gene estimations of Pib and Pita by a differential system. These results suggest that the efficiency of detecting blast resistance genes through use of DNA markers is dependent on the rice variety and the DNA markers. The proper markers for the Pita gene provide a basis for stacking other blast resistance genes into high-yielding and goodquality advanced breeding rice lines.