BACKGROUND: In an environment-friendly agriculture, plant extracts have been perceived as alternatives of synthetic pesticides. The Environment-friendly Agriculture Promotion Act of Korea has approved cinnamon extract as a matter for the production of commercial biopesticides. Thirteen commercial biopesticides containing cinnamon extract have been marketed locally. However, the analytical method for the quality control of these biopesticides containing cinnamon extract has not been studied. METHODS AND RESULTS: Cartridge clean-up method for the determination of cinnamaldehyde, cinnamylalcohol and salicylaldehyde in biopesticides containing cinnamon extract was developed and validated by gas chromatography (GC). The clean-up method was optimized with HLB SPE cartridges for the bioactive substance in biopesticides containing cinnamon extract, and the eluate was analyzed by GC. The developed method was validated, and the LOQ and recovery rates of cinnamaldehyde, cinnamylalcohol and salicylaldehyde were 0.139, 0.067 and $0.062mgL^{-1}$ and 84.2, 86.5 and 82.1%, respectively. The contents of cinnamaldehyde, cinnamylalcohol and salicylaldehyde were analyzed using the developed method in the 13 commercial biopesticides. Results showed 0.06-17.37%, <LOQ-0.01% and <LOQ, respectively. CONCLUSION: This method would contribute to manufacturers producing biopesticides and the quality control of biopesticides containing cinnamon extract.