The study aims to describe the distribution of patients with type 2 diabetes (T2D) by care plan and to highlight determinants of underuse and overuse of integrated care (IC). This cross-sectional study included all T2D patients resident in Reggio Emilia on 31/12/2015 based on the population-based diabetes registry. Eligibility for IC requires good glycaemic control, no rapid insulin, no kidney failure and no diabetes complications. We calculated the proportion of IC underuse and overuse and adjusted prevalence estimate using multivariate logistic regression. Determinants were age, sex, citizenship, district of residence and time since diagnosis. Of 29,776 patients, 15,364 (51.6%) were in diabetes clinic plan, 9851 (33.1%) in IC plan and 4561 (15.3%) not in any care plan (i.e., in Other group). There were 10,906 (36.6%) patients eligible for IC, of whom 1000 in Other group. When we adjusted for all covariates and restricted the analysis to patients included in care plans, the proportion of those eligible for IC plan but cared for in diabetes clinic plan (i.e. underuse of IC) was 28% (n = 3028/9906; 95%CI 27-29). Similarly, the proportion of those not eligible for IC but cared for in IC plan (i.e. overuse of IC) was 11% (n = 1720/11,896; 95%CI 10-11).The main determinant of both IC underuse and overuse was the district of residence. Foreign status was associated with underuse (37%; 95%CI 33-43), while old age (≥80 years) with both underuse (36%; 95%CI 0.33-0.38) and overuse (23%; 95%CI 22-25). The criterion for suspension of IC plan most frequently found was renal failure, followed by hospitalization for diabetes-related complications. Patients are more often allocated to more specialized settings than not. Healthcare provider-related factors are the main determinants of inappropriate setting allocation.