The aim of the present study was to determine the effect of passive smoking on the levels of salivary TAS, TOS, LL-37 and dental status in children.In the study the parents of children were asked to fill out a complete survey about smoking habits. After filling out the questionnaire, according to the survey results, a total of 180 children were included to the study as follows; 90 children exposed to passive smoking, and 90 children in the control group (unexposed controls). Also demographic data were recorded (age, gender, parental education levels, child's tooth-brushing habit and child's daily dietary sugar exposure, family income). Dental examination of children were performed and caries prevalance of the patients were recorded. Unstimulated saliva samples were collected from children. Saliva 'cotinine levels' which are expected to increase in passive smoking group; 'antimicrobial peptide LL-37' and oxidative stress markers 'total antioxidant status' (TAS), and' total oxidant status' (TOS) were evaluated by using Enzyme-linked immunosorbent assay (ELISA). The obtained data parameters of the two groups were evaluated and comparison was performed.