OBJECTIVES Chronic kidney disease (CKD) is leading condition of several comorbidities with additional social economic burden. The study aims to estimate the economic impact of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) on the social cost of a patient with CKD (stage IV and V pre-dialyses) in Italy. METHODS All adult outpatients in charge of 14 main Hospitals Centers in Tuscany Region have been enrolled during 7 week in the cross sectional study. Direct medical costs have been estimated using tariff for laboratory test, diagnostic exams, visits and hospitalization and price for drugs. Non medical costs included the cost of diet, patients and caregivers travel expenses, domestic help and informal care. The loss of productivity of patients and caregivers have been estimated as indirect costs using the human capital approach. The incremental effects of having comorbidities on social cost of CKD were estimated by multivariate Generalized Linear Models (log link, Gamma family) adjusting for gender, age and stage of CKD. Costs are expressed in Euro 2012. RESULTS Among