A reversed-phase high performance liquid chromatographic method was developed for the determination of cyclosporine A from chitosan nanoparticles. Ibuprofen was used as internal standard. The separation was achieved on a Phenomenex C18 column (150 x 4.6mm, 5 mu m) using 60: 20: 20, acetonitril: methanol: water mixture at pH 4 as mobile phase under isocratic conditions. The system was operated at 80 degrees C and the flow rate of mobile phase was adjusted to 1 mL/min. The detection wavelength was set at 205 nm. The calibration curve was linear from 2 to 150 mu g/mL with correlation coefficient values from 0.9994 to 0.9997. The lower limit of quantification 2 mu g/mL and limit of detection was 0.5 mu g/mL. Recovery was 99-101 % and the intra-and inter-day coefficients of variation were 0.94-2.32 and 2.52-3.45 %, respectively depending on the concentration. The method was found to be specific, accurate, precise and sensitive for the determination of cyclosporine A from chitosan based drug delivery systems.