Polymorphonuclear leukocyte (PMN) adherence to nylon was assayed in blood obtained from 10 malnourished patients before and during therapy with total parenteral nutrition (TPN). All patients demonstrated minimal to moderate loss of visceral and somatic protein. Adherence of PMN was unaltered by malnutrition or during the 4 wk of TPN in spite of hyperglycemia, which required insulin therapy in 4 patients. There was no correlation of blood sugar levels and PMN adherence.