A field experiment was conducted to study the field efficacy, net profit and cost benefit ratio of certain insecticides against fruit borer, Helicoverpa armigera (Hubner) in tomato during Rabi season 2008. The pooled and statistical data indicated that spraying of endosulfan 35 EC was found to be most effective as it recorded lowest larval population (2.33 larvae per plant) as compared to control (7.02 larvae per plant). Endosulfan 35 EC recorded significantly lowest fruit damage (22.85 per cent). Further, the present findings revealed that the per cent of fruit damage caused by fruit borer was highest at the beginning of the picking seasons and as the number of pickings increased there was a decrease in the fruit damage. All the insecticidal treatments significantly recorded lower fruit yield losses as compared to control (50.85

per cent). Maximum fruit yield was registered by treatment endosulfan (69.50 q/ha) which was followed by cypermethrin

(64 q /ha) and fenvalerate (61.33 q/ha) and lowest in control (20.33 q/ha). The net profit ranged from ` 7,424/- per ha (ë-cyhalothrin) to ` 38,528/- per ha (endosulfan). Spraying of cypermethrin twice on tomato crop, gave maximum cost benefit ratio (1:0.98) which was obviously due to its low price as compared to other insecticides.