Introduction: Esomeprazole (ESM) and Lansoprazole (LNZ) are proton pump inhibitors, used in the treatment of peptic ulcer and gastroesophageal reflux disease. Different marketed generic products for both drugs are now available in Saudi market as enteric coated dosage form. Different factors can affect the drug release from enteric coated formulation, and therefore, the final product should be tested. Methodology: In this study three different ESM generic products (20 and 40 mg) and four LNZ generic products (15 and 30 mg) were assessed and compared to the innovator products based on quality control tests. Results: For ESM, it was found that the content uniformity results for the innovator product (Nexium®) and all other generic products lies between 85-115% with relative standard deviation (RSD) less than 6%. Also, the calculated Acceptance values (AV) was less than 15% (L1), which met the US Pharmacopeia. The in-vitro dissolution test in acid stage for Nexium® and other ESM generic products was less than 10% which met the requirement. In case of LNZ, 4 different generic enteric coated pellets filled in capsules were studied and compared to its innovator (Lanzor®), the content uniformity results showed that all products met the requirement with AV less than 15%. The in-vitro dissolution studies showed that all products met the requirement and release less than 10% of the drug in the acidic media, except LNZ-P2 containing both 15 and 30 g LNZ, which exhibited release more than 10% in the acids stage. Conclusion: post-marketing assessments for drug products play an important rule to figure out the non-effective products.