The use of unlabelled immunotherapy (rituximab) in treatment of relapsed NHL proven by many studies done a high efficiency rate with a relatively fewer side effects compared to other conventional therapeutic modalities. Thus rituximab therapy has substantially changed the practice of lymphoma treatment. Although rituximab on its own has a relatively low complete response rate (6%) and overall response rate (48%), it is an effective therapy.The two other approved radiopharmaceuticals which are currrently used are Zevalin and Bexxar. Both Zevalin and Bexxar therapies are safe and effective in the treatment of NHL when used as directed and must be considered when standard treatments are ineffective. They are efficacious in patients who had failed rituximab therapy.