Background: Convulsion is a common problem in children due to different reasons. One of the suspected etiology is lead poisoning. We are exposed to lead in air, water, soil, food and also contaminated products in Tehran. In this trial we investigated the probable role of lead in producing or predisposing convulsion in children. Methods: A prospective case/control study was conducted (2012-2014) in 2 referral Hospitals in Tehran, Iran. One ml of CSF obtained from children, lead level determined by atomic absorption test. ROC curve illustrated. The AUC (Area under Curve), sensitivity, specificity, PPV, NPV of test calculated, P<0.05 considered meaningful. Results: Of 30 children; 15 diagnosed as epileptic (case) and remaining was non-epileptic (control)). The AUC was 0.588 (1-0.443, P value=0.2). The cut-off level (>1.65 μg/dl) had 70% sensitivity, 46% specificity, 56% positive predictive value and 60% negative predictive value for discriminating the epileptic from non-epileptic patients. The mean value of lead concentration had no meaningful difference between cases and controls (3.43+3.07 vs. 2.78+2.77 μg/d; p=0.3), and was not related to type of convulsion (p=0.7). Conclusion: Even low CSF lead level (1.65 μg/dl) had justifiable sensitivity (70%), albeit lower specificity (46%), to differentiate epileptic from non-epileptic cases but it does not mean as causative effect. Probably, the ambient air lead pollution in Tehran could predispose children to convulsion. Obviously this is not only air pollution, but also drinking water, household articles, toys and paint should be considered in our country.