A field experiment comprising 12 treatment combinations of four weed control methods (atrazine at 1.0 kg ha- ', isoproturon at 1.25 kg ha- ' , pendimethalin at 1.2 kg ha- ' and farmer's practice) and three fertility levels (N50P50K25. N75P75K375 and N,ooP,ooK5o) was conducted at Kukumseri during four consecutive summers of 2000, 200 I, 2002 and 2003. Pendimethalin at 1.2 kg ha" was very effective against Digitaria sanguinaUs. While atrazine at 1.0 kg ha- ' gave lowest count of Amaranth sp. Atrazine recorded lowest total weed dry matter and significantly higher tubers planr', tuber yield (32.5 t ha"), net return (Rs. 93232 ha- ' ) and B : C ratio (2.53). Pendimethalin and isoproturon were equally good in influencing seed potato yield. Increase in fertility level increased number of tubers, tuber weight planr' and tuber yield significantly. 100 kg N, 100 kg PP5 and 50 kg Kp resulted in 18.6% higher yield and thereby tended to fetch Rs. 18564 more net returns ha- ' as compared to 50 kg N, 50 kg PP5 and 25 kg Kp ha· '.