A new in vitro method was developed for evaluating field resistance to panicle blast in rice cultivars. Effectiveness of the method was examined over three seasons (1994-1996) using 29 rice cultivars and strains with different levels of field resistance to the disease. Panicles (including the boot leaf and one culm node) were detached from field grown rice plants at full heading. Each of the cut panicles was placed in a glass tube containing water. Neck nodes of the cut panicles were then wrapped in rectangular filter paper (5×7 mm) soaked in a spore suspension (5×10⁵ conidia/ml) of Pyricularia grisea. Lengths of blast lesions downward from the panicle neck nodes were measured 15 days after the inoculation. Lesion length was positively correlated with the percentage of diseased spikelets with panicle blast in field trials (significant at P<0.01). The results show that the method is useful for the evaluation of field resistance to panicle blast in rice cultivars.