This article reviews the various techniques of sampling used for the quality control of blood cell products. The importance of this stage for the validity of quality control results is emphasized. Three sampling methods, i.e., stripping, the sterile connection of sampling bag and the destructive method, are described in the form of operating modes and analyzed according to their advantages and drawbacks. The results of a comparative study carried out by the working group 'Blood Cell Products' of the French Society of Blood Transfusion are presented, showing that each method is valid and permits one to obtain a representative sample of the product to be controlled. Thus the diversity of the sampling methods allows us to select the one most adapted to the product to be controlled and to the analyses to be carried out afterward.