Field trials were conducted during the 2019-2020 cropping season to assess the efficacy of S-metolachlor and flumetsulam (triazolopyrimidine sulfonanilide)+S-metolachlor (chloro-acetanilide) pre-emergence herbicides in controlling weeds in maize at Chisumbanje estate. The experiment was laid out as a randomised complete block design (RCBD) with three treatments and replicated thrice. Treatments used include hand weeding (control), S-metolachlor and flumetsulam (triazolopyrimidine sulfonanilide)+S-metolachlor (chloro-acetanilide) herbicide. The data collected was based on weed density, plant height, maize grain yield indicating significant differences (p<0.05) amongst the treatments. Flumetsulam (triazolopyrimidine sulfonanilide)+S-metolachlor (chloro-acetanilide) scored the least weed density per m-2 as compared to S-metolachlor showing that it is an effective pre-emergence herbicide (33, 27 and 22) on Mexican marigold (Tagetes minuta), shamva (Rottboellia cochinchinensis) grass and wild jute (Corchorous tridens) respectively. The control (hand weeding) scored the highest weed density per m-2, indicating that the method was not effective as compared to S-metolachlor and flumetsulam (triazolopyrimidine sulfonanilide)+S-metolachlor (chloro-acetanilide) treatments. Flumetsulam (triazolopyrimidine sulfonanilide)+S-metolachlor (chloro-acetanilide) scored the highest yield of 10 tonnes/hectare whilst S-metolachlor and control scored 7.6 and 5.6t/ha respectively. Herbicides reduced the weed spectrum in maize resulting in realisation of higher yield in flumetsulam (triazolopyrimidine sulfonanilide) + S-metolachlor (chloro-acetanilide) experiment followed by S-metolachlor. Farmers are recommended to use flumetsulam (triazolopyrimidine sulfonanilide)+S-metolachlor (chloro-acetanilide) as a pre-emergence herbicide in controlling weeds in maize so as to realise higher yields and low weed density.