UV Derivative spectra were used for the direct quantitative determination of sulfacetamide sodium in distilled water. The quantification was accomplished using the integrated area under the peaks. The zero-order spectrum of sulfacetamide sodium shows an absorption band at λ = 258 nm, with an ε max = 14900 l. mol -1 . cm -1 , the determination limit was (0.55-25.4) µg/ml with R 2 = 0.9999 and RSD =1.25 %.The determination limits were (0.25-50.80) µg/ml for both first and second-order derivatives with R 2 = 0.9982, 0.9995 and RSD = 1.60 %, 2.40 % respectively. This indicates a more sensitive and accurate results as compared with the zero-order method. These methods were applied to the direct determination of the samacetamide eye drop.