Low birth weight (LBW) is a major factor in increased mortality, morbidity and disability neonates, infants and children that provide long-term impact on life in the future. Some risk factors for low birth weight is maternal age less than 20 years old or over 35 years old, pregnant women who have spacing of pregnancy less than 2 years old, hemoglobin levels mother stating the mother anemia and several other factors. The objective of study was to determine the relationship of age, spacing of pregnancy and hemoglobin levels of pregnant mothers with LBW at Arifin Achmad General Hospital of Riau Province. This study used an analytical method with cross sectional approach. The subjects were all mother gave birth during 2014 at Arifin Achmad Gemeral Hospital of Riau Province. There were 90 subjects with maternal age at risk amounted to 36 mothers (40%), the mother has a range of risk births by 20 mothers (22.2%), mothers are anemic as many as 16 mothers (17.8%) and babies born with low birth weight were 42 infants (46.7%). Statistical test results maternal age categories risky, p value = 0.001 means significant correlation between age and the incidence of low birth weight. Statistical test result categories spacing has a value of p = 0.932 and category levels of hemoglobin (Hb) of pregnant women have a value of p = 0.985 means that there is no significant relationship between birth spacing and maternal hemoglobin concentration with LBW.