The first order derivative of UV spectrometry method for simultaneous determination of Propranolol hydrochloride (PRO) and Flunarizine dihydrochloride (FLU) in pure bulk drug and combined dosage form was found to be simple, accurate, fast, precise and reproducible. The first derivative values measured at 289nm for PRO and 253nm for FLU. The linearity for zero order derivative method was carried out by using the concentration range 4-28µg/ml for PRO and 3-7µg/ml for FLU. The coefficient correlation of PRO and FLU for zero order was found to be 0.9995 and 0.9991 respectively. At zero crossing point of PRO (289nm) FLU showed a measurable derivative absorbance where as at the zero crossing point of FLU (253nm), PRO showed appreciable derivative absorbance value. The coefficient correlation of PRO and FLU for first order derivative was found to be 0.9991 and 0.9995 respectively. Precision study showed that % RSD was within the range of acceptable limits (<2). The % recovery for PRO and FLU was found to be in the range of 98-102% and 100-101% respectively. The percentage assay was found to be as 99.5 and 100.12% for PRO and FLU. The results of analysis have been validated as per ICH Q2 (R1) guidelines. This method has applied successfully for the determination of PRO and FLU in its combination with a high percentage of recovery good accuracy and precision. . Development and validation of first order derivative UV Spectrophotometric method for simultaneous estimation of Propranolol hydrochloride and Flunarizine dihydrochloride in bulk and combined dosage form. Int. Res. J.