A simple, sensitive, accurate and precise liquid chromatography mass spectrometry (LC-MS) method was developed for determination of pyrimethamine and sulfadoxine in pharmaceutical formulation. The chromatographic separation was performed on Phenomenex C18 column (I.D. 250 mm x 4.6mm, 5μm) and the column oven temperature was set at 30 ºC, with an injection volume of 5 μl, acetonitrile and Phosphate buffer in the ratio 75: 25 (v/v) at pH 2.5 as mobile phase. The Electrospray Ionization (ESI) was performed using nitrogen gas to assist nebulization (flow rate was set at 1.0 mL/min), the mass spectrometer was operated in the multiple reaction monitoring (MRM) mode. As part of the method validation, specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, accuracy, precision and robustness were determined. The limit of detection and limit of quantification for pyrimethamine and sulfadoxine were 0.69 and 0.82 ng/mL, and limit of quantification for pyrimethamine and sulfadoxine were 2.29 and 2.73 ng/mL respectively. The intra- and inter-day precisions were lower than 0.53% while the accuracy ranged from 99.99% to 100.11%. The admissible robustness indicates that the method remains unaffected by small but deliberate variations.