Mycobacterium tuberculosis, the causative agent of tuberculosis, is one of the most effective human pathogens. The mycobacterial cell envelope contains lipoglycans, and of particular interest is lipoarabinomannan (LAM), one of the most potent mycobacterial immunomodulatory molecules. The importance of lipoarabinomannan (LAM) in the immunopathogenesis of tuberculosis has incited structural studies on this molecule to (1) establish a precise structural model of the molecule and (2) decipher the structure/function relationships. In recent years, we have focused on the two domains essential for LAM biologic activities: the mannosyl-phosphatidyl-myo-inosi-tol anchor and the caps. We review here the recent procedures developed for the structural analysis of these domains.