Field experiment was conducted during the summer seasons of 1999 and 2000 at Kukumseri to evaluate some herbicide mixtures for controlling weeds in potato on sandy loam soil. Combinations of atrazine 0.75 kg ha" with isoproturon 1.0 kg and pendimethalin 0.9 and 0.6 kg ha", atrazine at 1.0 kg ha", pendimethalin at 1.2 kg ha", hand weeding twice and farmers' practice (earthing up at 80% emergence) being statistically at par, resulted in significantly lower dry weight of weeds than other herbicide mixture and check treatments. However, all the combinations of atrazine 0.75 and 0.5 kg ha" with isoproturon 1.0 and 0.75 kg ha" and pendimethalin 0.9 and 0.6 kg ha" except atrazine 0.50 kg+isoproturon 0.75 kg ha" and atrazine 0.50 kg+pendimethalin 0.6 kg ha", atrazine at 1.0 ha", isoproturon at 1.25 kg ha" and pendimethalin 1.2 kg ha", hand weeding twice and farmers' practice being statistically similar produced significantly higher tuber yield than weedy check. All herbicide treatments were superior to hand weeding twice and farmers' practice in influencing marginal benefit: cost ratio (MBCR). Highest MBCR (72.2) was resulted following the application of isoproturon at 1.25 kg ha" and was followed by atrazine at 1.00 kg ha"

(69.4).