The occurrence of multiple primary malignant tumor is a rare finding in Clinical observations and evaluations with review of journals were made on 12 cases of multiple primary malignant tumors which were experienced at Presbyterian Medical Center Chunju. It Seems apparent that certain individuals have an unusual predisposition or a sceptivity to and that the incidence of multiple primary malignant tumor is much too great to be due to chance Every effort should be made to discover other occult malignancies in patient who is being treated for a known tumor, and special aggressive and diligent follow-up of this patient is warranted.