BackgroundLow birth weight remains a major public health problem affecting developing countries. Evidence shows that low birth weight has long lasting negative health consequences through its contribution to stunting, mental impairment and non-communicable chronic diseases in later life. Thus, it is worth investigating the role of nutritional factors as determinants of low birth weight to suggest nutritional interventions to curb its negative health outcomes. This study aimed to investigate the determinants of low birth weight with main focus on the role of nutritional factors in Ethiopia.MethodsA facility-based case-control study was conducted from 3 February to 29 April, 2017. The data were collected using structured, pretested interviewer-administered questionnaire in all public health facilities of Dessie Town. Anthropometric measurements were made following standard procedures for both mothers and their newborns. Consecutive live births of < 2500 g and two succeeding normal weight babies were selected as cases and controls, respectively. Data were entered in to Epi-data software version 3.1, and exported to SPSS version 21, and analyzed using frequency, mean and percentage. Factors with p < 0.25 during bivariate analyses were entered into a multivariable logistic regression model to determine significant determinants of LBW. Statistical significance was considered at p < 0.05. Results were reported with odds ratio and 95% CI.ResultsMean ± SD of birth weight (g) was 2138 ± 207 for cases and 3145 ± 415 for controls. After adjusting for potential confounders using multivariable logistic regression analysis, the absence of iron and folate supplementation, receiving no nutritional counseling and consuming no additional meal, maternal undernutrition, maternal anemia and inadequate dietary diversity during the current pregnancy were found to be significant determinants of low birth weight in our study.ConclusionLack of nutritional counseling, absence of additional meal intake and iron and folate supplementation during pregnancy, and maternal undernutrition, maternal anemia and inadequate maternal dietary diversity were significant determinants of low birth weight. The importance of nutritional counseling, improving iron and folate supplementation during pregnancy, and nutritional status of pregnant women need to be strengthened to reduce the incidence of LBW in Ethiopia. In addition, behavioral change communications targeting pregnant women to improve women dietary diversity and their extra meal intake practice need to be enhanced in Ethiopia.