Atmospheric pollution is a global public health problem. The adverse effects of air pollution are strongly associated with respiratory and cardiovascular diseases and, to a lesser extent, with adverse pregnancy outcomes. This study analyzes the relationship between exposure to PM10 and low birth weight in the city of Santo André, São Paulo State, Brazil. We included babies born to mothers resident in Santo André between 2000 and 2006. Data on daily PM₁₀ levels was obtained from the São Paulo State Environmental Agency. We performed descriptive analysis and logistic regressions. The prevalence rate of low birth weight was 5.9%. There was a dose-response relationship between PM₁₀ concentrations and low birth weight. Exposure to the highest quartile of PM₁₀ (37,50µg/m³) in the third trimester of pregnancy increased the risk of low birth weight by 26% (OR: 1.26; 95%CI: 1.14-1.40) when compared to the first quartile. The same effect was observed in the remaining trimesters. This effect was observed for ambient particle concentrations that met the current air quality standards.