INTRODUCTION: Acute lower respiratory tract infections (predominantly pneumonia) account for one-third of all childhood deaths in developing countries. As ZINC DEFICIENCY results in impaired immunocompetence, and because ZINC supplementation improves immunity, the role of ZINC DEFICIENCY in the incidence of acute lower respiratory infections was investigated by comparing ZINC levels in children with pneumonia with healthy ones in this study. METHODS: Twenty-seven children admitted to the Pediatrics Ward of Alzahra Hospital (affiliated to Isfahan University of Medical Sciences) during one year were included in this conventional descriptive-comparative study. In these children, simulating and underlying causes for pneumonia, as well as reactive airway disease were ruled out. Scalp hair from occipital area was cut and ZINC content was measured with Neutron Activator Analysis (NAA). RESULTS: In the case group, male to female ratio was 1.1/1.6, mean age was 58.4±48.9 months, mean weight was 17.52±10.2 kg, and mean height was 99.4±26.39 cm, with no significant difference between the case and control groups. Growth parameters were similar in the two groups. Hair ZINC level was higher in the control group than in the case group (117.32±50.9 ppm and 88.24±45.1 ppm, respectively P<0.03). A significant direct correlation was found between ZINC level and age in both groups (P<0.05). DISCUSSION: This study supports the role of ZINC in immunity to lower respiratory infections. In view of the substantially lower level of hair ZINC in the control group compared to other countries, evaluation of the causes of ZINC DEFICIENCY and .effectiveness of ZINC supplements is recommended for other extended studies.