Abstract Background Income is an important predictor of adult mortality, as a proxy of living conditions, capability and access to health services. Previous studies show that mortality decreases by increasing income. In Italy, studies at a national level are missing. This study aims to investigate inequalities in mortality by income in Italy. Methods The analysis is based on the integration of the National Population Register (comprising the resident population as of Dec 31, 2018, and deaths in 2019) and the Income Statistical Register (representing perceived income during 2018). This integration enabled the availability of information on age, sex, residence, education, income, and vital status at the individual level for 13 million people aged 65 or above. Individuals were categorized according to their individual disposable income quintiles both before and after disability benefits. Inequalities by income are assessed by mortality rate ratios (MRR) estimated using negative binomial regression models controlling for demographic and socioeconomic features. The study is carried out within the Next Gen EU-funded project “Age-It Ageing well in an ageing society” (PE0000015), NRRF, M4.C2, Intervention 1.3. Results Considering income net of disability benefits, lower income levels are associated with higher mortality rates compared to the highest income level, for both sexes. Inequalities are more marked for men. The highest excess was observed for individuals with the lowest income (male MRR=1.65, 95%CI: 1.6-1.71; female MRR=1.43, 95%CI: 1.38-1.48). The excess decreases with increasing income. Conclusions The observed relationships between income and mortality are crucial for targeting policies to reduce health inequalities and promote the well-being of the elderly, the goal of which should be to improve access to social and health care and develop supportive policies for the most disadvantaged people. Further research will be devoted to the use of household income for individuals. Key messages • For the elderly, lower income levels are associated with higher mortality, with wider disparities in men. • The choice of definition of income is essential for an accurate assessment of the association between income and mortality.