The present study describes the systematic development and validation of RP-HPLC method for the estimation of Fipronil and Methoprene in its combined dosage form. The analysis was conducted using a Shimadzu Shim-pack GIST C18 column and Acetonitrile: Water (80:20, %v/v) as the mobile phase, with UV detection at 264nm. The method exhibited good separation, with retention times of 3.1 min for Fipronil and 4.71 min for Methoprene. The calibration curves showed excellent linearity over the concentration range of 20-100 μg/mL, with high correlation coefficients (R2) of 0.999 for Fipronil and 0.997 for Methoprene. Precision and robustness testing yielded %RSD values of less than 2%. The assay results for Fipronil and Methoprene were 99.02% and 99.63%, respectively, indicating high accuracy with significant % recovery. The method also met acceptance criteria for theoretical plates count, tailing factors, and other validation parameters as per ICH Q2 (R1) guidelines. Therefore, this accurate and precise RP-HPLC method can be reliably used for routine analysis of Fipronil and Methoprene in quality control laboratories