Cotrimoxazole is an association of two anti-infectives Sulfamethoxazole and Trimethoprim. It is a broad-spectrum antibiotic active against a wide range of microorganism (bacteria, fungi and protozoa). It is also used for the prevention of opportunistic infections in HIV-AIDS patients when the l CD4 level is between 350-500/mm3. For this reason, it is necessary to ensure the quality of the medicine administered to our population. The purpose of the present study was to assess the quality of the generic Cotrimoxazole 480 mg tablets marketed in the Douala city. A total of 37 lots of drugs were analysed, six (6) collected in the private organizations, seven (7) in the public sector and twenty-fourth (24) in the illegal market using the cluster sampling poll method. These drugs were therefore submitted to standards pharmaco-technical and physico-chemical tests. Accordingly, the tests of disintegration, hardness, friability, mass uniformity, dimension uniformity, identification and the dosage of the active compounds demonstrated 33% of non-compliance in the private sector, 86% in the public sector and 79% in the illegal sector. In conclusion, the study revealed that non-conformities affected the official sector (private and public) as well as the illegal in Douala market.