An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh during the period from July to December 2019 to study the effect of cultivar and seedling age on the performance of short duration transplant Aman rice. The experiment comprised four Aman rice cultivars, viz., BRRI dhan49, BRRI dhan56, BRRI dhan66 and BRRI dhan71, and four seedling ages viz. 20, 25, 30 and 35-day old seedlings. The experiment was laid out in a randomized complete block design with three replications. Results of the study showed that growth, yield and yield contributing characters were significantly influenced by cultivars, seedlings age and their interactions. At growth stage, BRRI dhan49 with 20-day old seedlings produced the tallest plant (57.67 cm and 67.33 cm, respectively), the highest number of total tillers hill-1 (15.00 and 13.67, respectively) and total dry matter (8.03 g m-2 and 11.50 g m-2, respectively) at 30 and 50 DAT. At harvest, the highest number of total and effective tillers hill-1 (12.82 and 12.00), longest panicle (24.50 cm), highest number of grains panicle-1 (128.80), heaviest 1000-grain weight (23.17 g), highest grain yield (5.35 t ha-1) and highest harvest index (51.69 %) were obtained from the cultivar BRRI dhan66. While, thirty-day old seedlings produced the highest number of total and effective tillers hill-1 (13.46 and 12.70), longest panicle (24.67 cm), highest number of grains panicle-1 (136.90), highest grain (5.62 t ha-1) and straw yields (5.81 t ha-1) and harvest index (51.67 %). In case of interactions, BRRI dhan66 with 30-day old seedlings produced the highest number of total and effective tillers hill-1 (14.67 and 13.97), longest panicle (26.00 cm), highest number of grains panicle-1 (146.7), highest grain yield (6.31 t ha-1) and highest harvest index (52.72 %). So, result of the present study reveals that BRRI dhan66 with 30-days old seedlings was found to be the best for obtaining maximum grain yield.