A sensitive, accurate and precise stability-indicating gas chromatography mass spectrometry (GC-MS) method was developed for simultaneous determination of lumefantrine and artemether in pure form and pharmaceutical formulation.In this study, comprehensive stress testing of lumefantrine and artemether have been carried out according to ICH guidelines Q1A (R2). Lumefantrine and artemether were subjected to forced degradation studies under hydrolytic (acid and base), oxidative, photolysis, and thermal stress conditions. The chromatographic separation was performed usinga ZB5 column with (30 m ×0.53 mm, 1.50 µm), and helium as a carrier gas. The proposed method showed well separation between the drugs and their degradation products and had a good accuracy. The method was linear with 12-120 ng mL-1 and 4-40 ng mL-1 for lumefantrine and artemether respectively. The method showed to be linear (r2 > 0.999), precise (RSD