Flowering time in parental lines plays a vital role in hybrid rice seed production. Transplanting rice seedlings at the right age assumes special significance in obtaining higher yields in cultivation as well as in hybrid seed production. In conditions where timely planting is not possible because of unavoidable circumstances, one is bound to transplant aged seedlings. In hybrid rice seed production, in spite of staggered seeding, simultaneous planting of male and female parents is preferred to avoid inconvenience and wasted labor. An experiment was therefore conducted during the 1994 wet season to find out the effect of seedling age at transplanting on flowering time in A, B, and R lines. The experiment was laid out in a randomized block design using five cytoplasmic male sterile lines along with their corresponding maintainers, six restorer lines, and one check variety in three replications at a spacing of 20 15 cm.