Abstract: A direct spectrophotometry for the determination of nonoxynol-9 in the contracptive films by using orthogonal polynomial method is presented. In order to eliminate the interferences of polyethylene glycol and polyvinylalcohol in the absorption spectrum of nonoxynol-9, the coefficient of quadratic polynomical was calculated over the wavelength rang of 263-283 nm at 4nm intervals, using six-point orthogonal polynomials. The mean recovery for mixtures was found to be 99.91+1.1%.The method has been used for quality control in manufacture.