Acute lower respiratory infections are the most frequent illnesses globally in children less than 5 years old. The aim of this randomized double blind controlled trial is to assess the effectiveness of zinc gluconate supplementation for 2 months period compared to placebo in reducing respiratory morbidity in acute lower respiratory infected children up to 5 years of age living in zinc poor population. Children were randomly assigned to receive either 10 mg zinc gluconate or placebo for 60 days. Demographic and clinical data were collected at baseline and every two weeks for 180 days. The final analysis included 96 children allocated equally to the two groups. The number of episodes of acute lower respiratory infections and severe acute lower respiratory infections were significantly lower in zinc group compared to placebo group (20.8% vs. 45.8% (P = 0.009) and 21.7% vs. 58.3% (P < 0.001), respectively). The acute lower respiratory infections free days were higher in the zinc supplemented group (P < 0.001). The median recovery time of morbidity was significantly shorter in zinc group (P < 0.001). Zinc supplement may result in significant reduction in respiratory morbidity among children with acute lower respiratory infections in zinc poor population. This study was registered under ClinicalTrials.gov Identifier no. NCT00536133.