Background: Micronutrient deficiencies may occur in patients with malignancy due to a variety of possible causes, including unbalanced dietary intake and adverse effects of treatment. In addition, many patients show signs of a chronic inflammatory response, which can affect circulating concentrations of certain vitamins and trace elements. Our aim was to examine the effect of the inflammatory response, as determined by plasma C-reactive protein (CRP) concentrations, on a range of micronutrients in patients with malignancy. Methods: Blood samples were collected from 50 patients with various malignancies for the measurement of vitamins A, E, C and B1, the trace elements copper, zinc, selenium and manganese and the inflammatory marker CRP. Vitamin A was measured as retinol and vitamin E as -tocopherol. Vitamin C measurement included both ascorbic acid and dehydroascorbic acid. The vitamins were assayed by high-performance liquid chromatography and the trace elements by atomic-absorption spectroscopy. Results: Concentrations of zinc and selenium below their respective reference ranges and copper and manganese above their respective reference ranges were commonly found in the cancer group. However, none of these elements showed any significant correlation with CRP (P >0.01). Reduced levels of vitamin A, C and B1 were commonly found in the cancer group. Vitamins A and C showed a significant negative correlation with CRP (rs=-0.66, P <0.0001 and rs=-0.53, P = 0.0005, respectively). Vitamin E showed no correlation with CRP. Conclusion: The inflammatory response is a major consideration in the interpretation of vitamin A and C concentrations in patients with malignancy.