Background: Geographical Information System is a new tool in environmental epidemiology that makes the opportunity of visualization and analysis of spatial data. The aim of this study was to determine the geographic variation of low birth weight using geographic information system in order to evaluate the efficacy of primary health care and health information system. Methods: Low birth weight records in rural areas of Rasht district (north of Iran) were collected from the records of health care centers and health houses. Electronic map of the Rasht district was collected from National Cartographic Center. Health information was collected from health surveillance data in each village. The three layers of data were analyzed using ArcView program. Results: The prevalence of low birth weight was 0.049. Using kernel smoothing method, three major and two minor hot spots were identified within Rasht district, mostly in northern part. Existence of health houses was found to be statistically significant in explaining low birth weight risk. Conclusion: This research examined geographic variation of LBW in Rasht district and found hot spot places. Existing of health house was associated with higher risk of low birth weight.