The object of this dissertation is to develop and implement magnetic resonance spectroscopy (MRS) techniques in the diagnosis, treatment monitoring, and basic understanding of the disease process in metabolic and neoplastic musculoskeletal disorders. P-31 MRS is used to do the following: detect chemotherapy- resistant human osteosarcomas implanted into a nude mouse model; determine anesthetic and temperature effects on spectra in the nude mouse model; monitor the metabolic changes in skeletal muscle that occur in peripheral vascular disease (PVD) patients with intermittent claudication; and compare metabolic changes in skeletal muscle of PVD and congestive heart failure (CHF) patients with age-matched normal volunteers. Development of P-31 MRS in the therapy monitoring of patients with musculoskeletal tumors is also presented. Water suppressed, proton magnetic resonance spectroscopy is developed for use in diagnosis and monitoring of the therapy response of musculoskeletal neoplasms including osteosarcoma.