Regular exposure to tobacco smoke at home causes airway inflammation and altered cytokine regulation; however, there is variation between individuals of different countries. To determine effects of passive smoking on plasma IL4, TNFá, and CRP in healthy male school-children in Khartoum. A total of 135 male school-pupils (69 passive smokers and 66 non-smokers) were selected randomly from three primary schools for boys in Khartoum. Information about smoking history was collected from each pupil and his parents using a questionnaire. Plasma CRP, IL4 and TNFá were measured using commercially available ELISA kits. Plasma IL4 and TNFá in the passive smokers (mean ± SEM) is at 2.92 ± 0.93 and 19.78 ± 4.67 pg/ml respectively; whereas in the non-smokers . It is at 0.45 ± 0.28 and 5.05 ± 1.54 pg/ml respectively. The difference between the two groups is statistically significant (p <0.05). The mean plasma IL4 and TNFá were lowest with no exposure, higher with moderate exposure, and highest with heavy exposure (P < 0.05). Plasma CRP showed insignificant difference between the two groups. Passive smoking causes significant rise in plasma TNFá and IL4 with a dose dependent effect among school-pupils in Khartoum.