Nepetalactones, the major chemical components of catnip (Nepeta cataria L.), were analysed by reversed-phase HPLC coupled with UV and MS detection. Two major nepetalactones, Z,E-nepetalactone and E,Z-nepetalactone, were successfully identified and quantified. The linearity range for Z,E-nepetalactone was determined as 0.00655-0.655 mg/mL with a correlation coefficient of 0.9999, and the linearity range of E,Z-nepetalactone was found to be 0.00228-0.456 mg/mL with a correlation coefficient of 0.9999, under UV detection at 228 nm. The linearity ranges were from 0.00164 to 0.0328 mg/mL, with a correlation coefficient of 0.9999, for ZE-nepetalactone and 0.00114-0.0228 mg/mL, with a correlation coefficient of 0.9999, for E,Z-nepetalactone by MS detection with selected ion monitoring of ion peak m/z 167. The MS detection was found to be more sensitive than UV detection and this method was validated as simple, reliable and sensitive for catnip nepetalactone analysis. This method can be used for identification and fingerprinting of catnip products.