Abstract: Background and Objective: Cucurbits are an important group of vegetables, which have great nutritional and medicinal value. However, stink bug (Coridius janus) is very destructive pest which significantly retards the production of cucurbit. There are many methods for the control (biological, chemical and cultural etc.) of bugs but the most effective method remains chemical control. Methodology: The prepared dilutions of acetameprid, imidacloprid and spinosad were evaluated in term of toxicity. A parallel control was also set for each insecticide. The experiment was conducted in Completely Randomized Design (CRD) with three replications. Results: The collected data was subjected to Probit analysis after converting the data into percent corrected mortality to determine LC50. The LC50 value showed that imidacloprid had more toxicity after 12, 24, 48 and 72 h exposure, spinosad showed less toxicity after exposure of 48 h and acetameprid showed very less toxicity after the exposure of 72 h. Conclusion: By this study it is concluded that imidacloprid toxicity against the adults of stink bug (Coridius janus) is greater than acetameprid and spinosad.