Multiple myeloma (MM) is a malignant B cell disorder characterized by the uncontrolled proliferation of monoclonal plasma cells (PC) in the bone marrow (BM) and the presence of monoclonal immunoglobulin in serum and/or urine. Despite recent advances in the understanding of the pathophysiology of MM, the exact etiology of MM still remains unknown. MM cells are characterized by a profound degree of genetic instability with several chromosomal abnormalities. The survival and proliferation of MM cells are largely dependent on a supportive microenvironment. The development and progression of MM can be regard as a multistep process of molecular alterations resulting in uncontrolled growth and therapy resistance. Although considerable progress has been made in the therapy of MM, it still remains an uncurable disease with conventional treatment. Novel therapeutic modalities targeting the MM cell and the microenvironment such as inhibitors of angiogenesis (thalidomide and derivatives, arsenic trioxide) and inhibitors of transcription factor NF-kappa B (proteasome inhibitors) are currently being evaluated in clinical trials and hopefully will result in prolonged disease-free and overall survival.