Introduction: Cancer-related malnutrition has negative consequences are taken too lightly in most oncology wards. The objective of this study is to determine the malnutrition risk (MR)/malnutrition (MN) in cancer patients using PG-SGA short form. Methods: This cross sectional study was conducted with cancer patients in oncology unit at Benghazi medical center on 229 patients in which 107 male and 122 female. The data collected through PG-SGA short form and analyzed by either frequencies or by suing Chi-square for significant differences. Results and discussion: The study enrolled 229 oncology patients. The mean age was 58.34 ± 11.60 years. One hundred and twenty tow (53.7.3%) of the patients were female. The most common three tumor types were breast tumors (27.9%) followed by colorectal cancer (14%) whereas, almost similar report for lung, liver and upper GIT (10.9%). (11.4%) and (11.8%) respectively . The mean BMI of the patients was 26.17 ± 0.3 kg/m2. According to PG-SGA short form of the patients were in moderate risk of nutritional status and overall score of PG-SGA short form was 18. 34± 0.56. Furthermore the prevalence of cancer in this study was significant high in male (P< 0.05) Conclusion: In cancer patients, the risk of malnutrition is significantly high, and this may alter the patient’s life quality and expectancy. Therefore, the nutritional status of the patient that is diagnosed with cancer should be assessed in early stages of the disease.