OBJECTIVES: The aim of this study is to assess and analyze health care expenditure trends by disease between 2012 and 2014, based on a top-down allocation of expenditure using the French health insurance database. METHODS: Using information about 56 millions of individuals from the general scheme insurance database (86% of the French population), we identified all people who received care for each of 57 groups of diseases or medical events or treatments, which are frequent, severe and/or costly. Algorithms have been applied to each patient, using ICD-10 diagnoses for long-term chronic diseases or hospital stays, specific drugs or medical procedures. Annual costs of all reimbursed expenditures (outpatient/inpatient care, disability/sickness benefits) were extracted per individual. A top-down method was used to allocate expenditure to each of the 57 diseases based on the average expenditure by disease calculated for individuals with only one disease. This was done for 2012, 2013 and 2014 in order to analyze trends. RESULTS: In 2014, among the 155 billion euros of expenditures (all insurance schemes), 33.9 billion were related to isolated hospitalizations with an average annual growth rate of 2%, 22.6 billion to psychiatric disorders and treatments (+1.8%/year), 16.1 to cancer (+3.6%/year), 16.2 to cardiovascular diseases (+.3.1%/year), 7.9 to diabetes (+2.6%/year), 6.9 to neurologic disorders (+3.6%%/year). The highest increase was observed for Liver/pancreas diseases, essentially due to hepatitis C drugs: +864 million € compared to 2012, giving a total of 2.3 billion € in 2014. A more detailed analysis of expenditures by diseases and of main cost drivers will also be presented. CONCLUSIONS: Our study provides helpful information to policy makers by monitoring the performance of the health care system at a disease-based level. This tool can also be used to forecast the impact of ageing and epidemiologic patterns on health expenditures.