Background: Highest intensity of soil transmitted helminthiasis (STH) is seen among school age children. The objective of this study is to find out the prevalence and factors associated with STH infection among school age children of 5-14 years in a rural area of Coimbatore district.Methods: After getting ethical clearance, five of the fourteen villages of Vedapatti were selected by cluster sampling method. Totally 819 participated in the survey conducted between November 2015-July 2016 in the field practice area. Consent from parents and assent from child were obtained. Structured questionnaire was used to collect information. Totally 610 gave one adequate stool sample. Early morning samples were collected and transported to the laboratory within four hours. Formal ether concentration method was performed and examination was done. Data analysis was done with SPSS-19 software. Prevalence is expressed in percentage with 95% confidence interval (CI). Univariate and Multivariate analysis were performed. Strength of association was expressed in terms of odds ratio and adjusted odds ratio with 95% confidence interval. P value <0.05 was considered as statistically significant.Results: The prevalence of STH was 7.70% (95% CI: 5.58- 9.82). Ascaris lumbricoides was highly prevalent 6.9% (4.89% to 8.91%) followed by hook worm 0.2(0.15% to 0.55%) and Trichuris trichura 0.7%(0.04% to 1.36%). Uni variate and Multivariate logistic regression analysis showed that pucca houses offered protection against STH.Conclusions: STH is still a public health problem in Coimbatore. When regular deworming is accompanied by appropriate sanitation and hygiene activities designed to prevent re infection of STH, a long-term impact can be achieved.