MAKALE ÖZETİ This study aimed to determine the levels of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) in metformin- and sitagliptin-containing pharmaceutical products using headspace gas chromatography–mass spectrometry (HS-GC-MS). NDMA and NDEA were detected in all analyzed samples, with concentrations exceeding the acceptable daily intake limits. These findings highlight the need for continuous monitoring of nitrosamine impurities to ensure the safety and quality of pharmaceutical products.