The aim of the study was to analyze the function of peripheral blood monocytes from patients with Non-Hodgkin’s lymphoma before and after incubation with zymosan and indomethacin. Peripheral blood samples were collected from 28 patients with malignant lymphoma (13 males and 15 females with age range 20-65) years. Their clinical record and pathologic material were reviewed. The control group consisted of 17 normal subjects, (9 men and 8 women) of age range of 20-45 years. The following investigations were carried out in all patients: Bactericidal activity against Escherichia coli. Level of superoxide anion and Chemiluminescence’s Technique for analysis of oxygen metabolite Results. The mean bactericidal indices of E. coli by peripheral blood monocytes without indomethacin were 56.75 (SD ± 10.5) in control group at 60 minutes and it was 36.88% (SD ± 11.3) in Non-Hodgkin’s lymphoma patients. The level of INT was greater in healthy control than NHL-patients. The improvement after addition of zymosan was significant in all groups. The peak generation of chemiluminescence in Non-Hodgkin lymphoma patients was 11256 x 10-3 CPM at 20 minutes and in healthy controls 16575 x 10-3 CPM at 5 minutes and after incubation with zymosan and indomethacin were 13843 x 10-3 CPM at 5 minutes in NHL patients and 16312 x 10-3 CPM in healthy controls. The time of appearance of CL peak improved in Non-Hodgkin’s lymphoma patients (p< 0.01) but there is no difference in the time of CL peak of the healthy controls.