Immunotherapy refers to treatment strategies based upon modulating the immune system either by activation or suppression to achieve a prophylactic or therapeutic goal. Strategies that enhance the immune response include active and passive ones. The active includes vaccination and adjuvants, adoptive T cell therapy, mAb therapy, NK cell therapy as well as cytokine therapy. While, passive immunotherapy includes antibody replacement therapy. Strategies that diminish the immune response,on the other hand, include anti-inflammatory agents (steroids and NSAIDs) as well as immuno-suppressive measures for RA, bronchial asthma and graft rejection. Strategies that alter the immune response include pre-emptive measures as Rh Ig therapy and antibiotic therapy, as well as modification of ongoing diseases by cytokines and allergy desensitization. Finally, immunotherapy also includes targeted therapy that targets one type of cell or antigen without injuring other cells. This review highlights the different modalities of immunotherapy with special concern on cancer.