This study assessed the strength of the association between socioeconomic status (SES) and low birth weight (LBW) and preterm birth (PTB) in Southwestern Ontario. Utilizing perinatal and neonatal databases at the London Health Science Centre, maternal postal codes were entered into a Geographic Information System to determine home neighbourhoods. Neighbourhoods were defined by dissemination areas (DAs). Median household income for each DA was extracted from the latest Canadian Census and linked to each mother. All singleton infants born between February 2009 and February 2014 were included. Of 26,654 live singleton births, 6.4% were LBW and 9.7% were PTB. Top risk factors for LBW were: maternal amphetamine use, chronic hypertension and maternal marijuana use (OR respectively: 17.51, 3.18, 2.72); previously diagnosed diabetes, maternal narcotic use and insulin-controlled gestational diabetes predicted PTB (OR respectively: 17.95, 2.69, 2.42). Overall, SES had little impact on adverse birth outcomes, although low maternal education increased the likelihood of a LBW neonate (OR: 1.01).