Background: Conjunctivitis is conjunctival inflammation or inflammation of the mucous membranes that cover the back of the eyelid. Thechanges in temperature and environment are one of the causes of conjunctivitis. In children the transmission of conjunctivitis is very high. The purpose of this study was to determine the incidence of conjunctivitis in children in coastal areas and at the mountainside. Methods: This study was used observational analytic with cross sectional design. The sample of this study was the medical record data of children with conjunctivitis in the period January 2016 - October 2017 in RSUD Panembahan Senopati Bantul and RS Aisyiyah Muntilan that meet the inclusion and exclusion criteria. Data analysis was used chi-square. Result:There were 209 patients (80.1%) and conjunctivitis in children in the hospital at the foot of the hospital, 52 (19.9%). There was differences in the incidence of conjunctivitis are significant at p = 0.000 between children in the coastal area with children who was at the mountainside. Conclusion: There was a significant difference in the incidence of conjunctivitis in children on the coastal area more than children at the mountainside.