BACKGROUND: We investigated whether multidisciplinary team-based primary care practice improves adherence to process of care guidelines, in the absence of financial incentives related to pay-for-performance.METHODS: We conducted a natural experiment including 135,119 patients, enrolled with a general practitioner (GP) in a multidisciplinary team Family Medicine Group (FMG) or non-FMG practice, using longitudinal data from Quebec's universal insurer over the relevant time period (2000-2010). All study subjects had diabetes, chronic obstructive pulmonary disease, or heart failure and were followed over a 7-year period, 2 years prior to enrollment and 5 years after. We constructed indicators on adherence to disease-specific guidelines and composite indicators across conditions. We evaluated the effect of FMGs using propensity score methods and Difference-in-Differences (DD) models.RESULTS: Rates of adherence to chronic disease guidelines increased for both FMG and non-FMG patients after enrollment, but not differentially so. Adherence to prescription-related guidelines improved less for FMG patients (DD [95% CI]=-2.83% [-4.08%, -1.58%]). We found no evidence of an FMG effect on adherence to consultation-related guidelines, (DD [95% CI]=-0.24% [-2.24%; 1.75%]).CONCLUSIONS: We found no evidence that FMGs increased adherence to the guidelines we evaluated. Future research is needed to assess why this reform did not improve performance on these quality-of-care indicators.