Background: Acute lower respiratory infection (ALRI)is the leading cause of child mortality ,especially in the developing world.Polymorphisms in the interleukin 4 (IL-4) gene have been linked to a variety of human diseases. Objectives: To investigate whether the IL-4-590L/T polymorphism could be a genetic marker for susceptibility to ALRLS in young Egyptian children. Methods: This was a multicentre study conducted on 480 children diagnosed with pneumonia or bronchiolitis ,and 480 well-matched healthy control children .using PCR RELP analysis , we genotyped a 590c/T single nucleotide polymorphism of the IL-4gene promoter, meanwhile the serum IL-4 concentration was measured by ELISA. Results: the frequency of the IL-4-590T/T genotype and T allele were overrepresented in patients with ALRIS in comparison to the control group )OR=2.0,[95%confidence interval:1.38-2.96] (OR=2.0; [95% confidence interval[CI]:1.38-2.96];fortheT/Tgenotype)and(OR:1.3;[95%CI:1.07-1.56];forthe Tallele;P<0.01).TheIL-4-590T/Tgenotypewasassociatedwithsignificantlyhigher for t/t genome was associated with significantly higher mean serum mean serum IL-4 concentration compared to C/T genotype (58.7±13.4pg/mL) Conclusion : the IL-4-590C/T polymorphism may contribute to susceptibility to ALRIS in young Egyptian children .