The 5q- syndrome is a myelodsyplastic syndrome (MDS) characterized by symptomatic anemia and an indolent natural history with low transformation potential. Our understanding of the molecular pathogenesis of this disease has advanced considerably, paralleled by the delineation of the relevant targets underlying selective lenalidomide sensitivity. The context in which one treats the 5q- syndrome, and all lower risk MDS, is critical. The focus of treatment should remain the amelioration of refractory cytopenias. In the 5q- syndrome, lenalidomide is the treatment of choice for patients with symptomatic anemia as it relieves the burden of transfusion dependence and iron overload in the majority of cases. We discuss herein the current understanding of the biology of the 5q- syndrome, actions of efficacy of lenalidomide and strategies for clinical management.