An experiment was carried out during T. aman season of 2014 at Soil Science Field Laboratory of the Department of Soil Science, Bangladesh Agricultural University, Mymensingh to study the effect of different levels of potassium supplied from two different sources on the growth and yield of rice variety BRRI dhan49. The experiment was laid out in a randomized complete block design with three replications having 5 m × 4 m unit plot size. There were seven treatment combinations viz. Control i.e K 0 kg ha-1 (T1), K 40 kg ha-1 as MoP (T2), K 50 kg ha-1 as MoP (T3), K 60 kg ha-1 as MoP (T4), K 40 kg ha-1 as K2SO4 (T5), K 50 kg ha-1 as K2SO4 (T6) and K 60 kg ha-1 as K2SO4 (T7) in the experiment. Basal dose of fertilizers @ 100 kg N, 15 kg P, 12 kg S and 2 kg Zn ha-1 were applied from urea, TSP, gypsum, zinc oxide, respectively for all treatments. The full doses of MoP were applied as per treatments. The results revealed that growth and yield contributing characters like plant height, number of tillers hill-1, panicle length, grains panicle-1 and 1000-grain weight responded significantly to different levels of applied K. The grain and straw yields of BRRI dhan49 were also significantly influenced due to different treatments. The highest grain yield of 4.9 t ha-1 and straw yield of 5.0 t ha-1 were obtained in T4 which was statistically similar to T3. The lowest grain yield of 3.5 t ha-1 and straw yield of 3.9 t ha-1 were found in T1. The K content and uptake by grain and straw were also higher in the treatment T4. The potassium supplied from MoP performed better than that supplied from K2SO4. Hence, the application of K @ 50 kg ha-1 as MoP may be recommended for successful cultivation of BRRI dhan49.