Context: The presence of dry eye syndrome (DES) in ocular allergic diseases was evaluated in several studies. Despite this, little exists about the tear film instability in atopic children including patients with allergic rhinitis (AR), allergic conjunctivitis (AC) and asthma. This is a study which presents intriguing findings regarding the relationship of tear film instability with clinical aspects in atopic children.Objective: To determine the tear film instability in children with AR, AC and asthma.Materials and methods: One hundred and thirty-five consecutive children with AR, AC and asthma as study group and 45 children without any systemic and ocular abnormality as control group were included in the study. Skin prick tests, measurement of tear film breakup time (TFBUT), serum immunoglobulin E and eosinophil counts were performed in all patients. Also four subgroups of patients were designated as AR group (Group I), AC group (Group II), asthma group (Group III) and control group (Group IV).Results: Socio-demographic characteristics were similar except for family atopy between the groups (p>0.05). The mean TFBUT was significantly lower in the study group (15.54.4s) than the control group (18.4 +/- 2.9s; p=0.000). Also, there was no significant differences in the percentage of the patients who has TFBUT<10s (p=0.066). In logistic regression analysis, atopy was found to be the determinant of lower TFBUT (OR=16.33, 95%; CI=1.17 to 228.05, p=0.03).Conclusion: The presence of tear film instability was higher in children with AC, AR and asthma. This finding should be taken in consideration in atopic children.