Introduction: In France, epidemiological surveillance of frailty and multimorbidity is not yet operational. The main objective of this study was to examine the feasibility of using national declaratory surveys to produce indicators of frailty and multimorbidity. Methods: Two surveys with similar methodologies but differing definitions of frailty and multimorbidity were used: the Health and Social Protection Survey (ESPS 2012) and the Disability-Health-Households Survey (HSM 2008). Participants aged 55 and older with no impairment in activities of daily living were selected. Frailty was defined using Fried’s phenotypic criteria. Multimorbidity was defined as the presence of at least two categories of diseases among cardiovascular and cerebrovascular diseases, diabetes, chronic respiratory diseases, and arthralgia. We compared the prevalences of frailty and multimorbidity between the two surveys using their 95% confidence intervals [95% CI]. Additionally, we described the characteristics of individuals in both surveys according to whether they were robust, frail, or multimorbid alone, or both frail and multimorbid. Results: The reported prevalences of frailty (11.1% [9.9%–12.3%] in ESPS and 12.3% [11.5%–13.0%] in HSM) and multimorbidity (14.9% [13.6%–16.2%] and 16.8% [15.9%–17.7%], respectively) were not significantly different between the two surveys. The variation in these prevalences by age and sex was also comparable. Finally, in both surveys, the distribution of individuals across the different groups (robust or frail and/or multimorbid) was very similar, and the characteristics of individuals within these groups followed the same trends. Conclusion: This study shows that it appears possible to use large-scale national self-report surveys for the epidemiological monitoring of indicators of frailty and multimorbidity. The use of standardized questionnaires remains essential for monitoring these indicators over time. It highlights the importance of frailty and multimorbidity in the non-dependent population aged 55 and over in France (approximately 5 million people at high risk of loss of independence). It also allows for the characterization of the specific characteristics of multimorbid and frail individuals in order to better guide preventive actions.