Field experiments were conducted under irrigated condition during winter seasons of 2020-21 and 2021-22 (September to February) at Cotton Research Station, Tamil Nadu Agricultural University, Srivilliputtur to study the comparative efficacy of mechanical and chemical weed management methods in cotton. Six treatments were evaluated in a randomized block design with four replications. The treatments consisted of control (no weeding), weed free check, pre-emergence application of (PE) pendimethalin at 1.0 kg/ha followed by (fb) one hoeing at 45 days after sowing (DAS), pendimethalin at 1.0 kg/ha fb post-emergence application (PoE) of pyrithiobac-sodium at 62.5 g/ha at 25 DAS fb one hoeing at 45 DAS, weeding by power tiller at 25 and 45 DAS, pendimethalin PE at 1.0 kg/ha fb weeding by power tiller on 25 and 45 DAS. Pendimethalin PE fb pyrithiobac-sodium PoE fb one hoeing recorded the higher cotton growth and yield attributes except boll weight along with lesser weed density and biomas and higher weed control efficiency. This was on par with that of pendimethalin PE fb weeding by power tiller at 25 and 45 DAS and pendimethalin PE fb one hoeing at 45 DAS and significantly superior than weeding by power tiller at 25 and 45 DAS. Application of PE fb PoE herbicide fb one hoeing also registered the highest seed cotton yield which were comparable with that of pendimethalin fb weeding by power tiller at 25 and 45 DAS. The cost of cultivation was drastically reduced by mechanical weeding. The economic analysis showed that higher net income and benefit cost ratio were associated with PE herbicide application fb weeding by power tiller at 25 and 45 DAS followed by weeding by power tiller at 25 and 45 DAS.