Primary health service use (P-HSU) may be influenced by predisposing and enabling factors measured at individual- and contextual-levels but is equitable when driven by need factors. Objectives: 1) Estimate the effect of residential location on maternal and child P-HSU; 2) Assess P-HSU inequity by determining whether the effects of need factors on P-HSU are dependent on predisposing and enabling factors; 3) Describe perceived unmet healthcare needs in the maternal-child population observed to have inequitable P-HSU. Methodology: The sample of 1451 mother-child pairs was from a prenatal cohort recruited from London, Ontario between 2002 and 2004, with follow-up until children were toddler/preschooler-aged. Individual-level data were linked by residential address to contextual-level data sourced from Statistics Canada. Two multilevel logistic regression models were built to assess the multilevel characteristics associated with P-HSU by mothers and children, and interactions of need factors with covariates were tested to assess P-HSU inequity. The prevalence of perceived unmet healthcare need was described, and a discussion on limitations of its measurement in the literature was performed. Results: P-HSU varied between neighbourhoods but only for mothers (p=0.02). Maternal obesity’s effect on P-HSU was different for rural mothers living in low-income households (OR=0.26, pConclusion:Results indicate that differences in maternal P-HSU exist between neighbourhoods, partially explained by urban/rural residence. Several enabling factors modified the effect of need factors on both maternal and child P-HSU, providing evidence for inequitable P-HSU. This research has the potential to inform Canadian healthcare policy with regards to contextual effects, P-HSU inequity, and perceived unmet healthcare needs in mothers and children