Background: - Low birth weight is associated with increased incidence of new born morbidity and mortality. Claim that babies who have a low birth weight have lower intelligence, poorly at school, and health or behavior problems in future lifespans. Aim of this research was to determine the effect of maternal nutritional status of mother during her pregnancy on birth weight and its determinant factors at public health facilities of fogera woreda. Methods and Materials: A health facility based cross sectional study was conducted among 422 women who were selected by systematic random sampling techniques and coming to health facilities for seeking of delivery service from January to April 2017. Data was collected using a semi-structured questionnaire and face to face interview. Epi-Info version 3.5.1and SPSS version 20 was used for data entry and analysis.Discripitive statics’ was done for proportions, frequency distribution, and Mean (Standard deviation). Multivariate logistic regression analysis also carried out to identify the associated and determinants of birth weight by controlling for possible confounding variables respectively. Statistical significance was considered at p-value <0.2and 0.05 for the bivariate and multivariable logistic regression analysis respectively. Results: - The proportion of low birth weight was 19.3%,95%C.I. [15.9, 22.9].Antenatal care, level of hemoglobin, type of pregnancy, pregnancy danger sign (blurred vision),iron foliate supplement,Hx of abortion and low birth weight ,and source of food were independent predictor of low birth weight. Conclusion and Recommendation: Maternal nutrition had direct effect on birth weight of new born, therefore improving nutritional status through maternal nutritional advice and screening during ANC follow up; continuous nutrition education and screening by HEWs through home to home visit can improve.