Thermosensitive genic male sterility (TGMS) is a new genetic tool used in developing commercial F1 rice hybrids. This study investigated the stage at which sterility occurs during anther development in TGMS lines. For critical examination, panicles were collected from TGMS lines TS16, TS18, TS29, and cytoplasmic male sterile (CMS) lines IR58025A and IR62829A. In the TGMS lines, the developmental stages of young panicles were examined at stages IV, V, and VI in September 1998 and May 1999 for the expression of fertility and sterility, respectively. Anthers were taken out from the spikelet and fixed in 70% alcohol for 1 h. These were then passed through a series of solutions containing alcohol and methyl salicylate in the proportion of 4:1, 3:2, 2:3, and 1:4, and finally in methyl salicylate for 15 min in each solution with two changes in the last step. Cleared anthers were mounted in methyl salicylate in a cavity microslide and examined using a Namarski differential interference contrast in a bright field microscope for optimal viewing and microphotography.