Recently, carbohydate-carbohydrate recognition has emerged as a new type of interaction in cell adhesion processes. One of these carbohydrates, the LewisX determinant (LeX), has been shown to be involved in murine embryogenesis. Here we confirm the existence of this specific interaction by measuring the adhesion between giant vesicles functionalised with synthetic Lex bearing lipids providing to the LeXdeterminent a high orientational freedom. This was obtained by micropipette aspiration and contact angle measurements. By using a simple model involving the several contributions to the adhesion free energy, specific and non specific interactions could be separated and quantified. In a second step, using natural Lex bearing sphingolipids, we could underscore the high sensitivity of LeX-LeX recognition to molecular structure and prove that the possible orientations provided by the natural LeX bearing molecules not only allow but strongly favor LeX-LeX recognition.