The B cell antigen receptor (BCR) plays a central role in the self/non-self selection of B lymphocytes and in their activation by cognate antigen during the clonal selection process. It was long thought that most cell surface receptors, including the BCR, were freely diffusing and randomly distributed. Since the advent of super-resolution techniques, it is has become clear that the plasma membrane is compartmentalized and highly organized at the nanometer scale. Hence, a complete understanding of the precise conformation and activation mechanism of the BCR must take into account the organization of the B cell plasma membrane. In my presentation I will summarize our current studies on the nanoscale organization of the B lymphocyte membrane and discuss how this new information influences our view of the conformational changes that the BCR undergoes during activation.