Introduction: In France, the Public Health Code mandates that the Maternal and Child Health Service (PMI) in each department organize health screenings for 4-year-olds enrolled in preschool. The objective of this study is to describe how these checkups were implemented by the PMI service in the Val-de-Marne department during the 2014–15 school year, with the aim of combining the epidemiological aspect of the health checkups with comprehensive individual screening. Materials and Methods: The checkup was conducted by a pair of paramedical staff who had received specific training. Data were collected electronically, prospectively, and anonymously: vaccination status, weight, height, dental and visual screening, pure-tone audiometry, and language and psychomotor assessments. Results: Among the 19,037 school-aged children, 18,502 were present on the day of the checkup (97%). One-quarter of the cohort (26%) attended school in a priority education zone (n=4,772). At the conclusion of the assessment, 10,747 reasons for referral were identified. The main reasons were: dental (24.5%), vision (22.7%), vaccination (21.0%), language (15.1%), height and weight (9.5%), hearing (5.2%), and psychomotor (2.2%). The majority of referrals (92%) resulted in an actual consultation. Discussion - Conclusion: The originality of this study lies in using the preschool health screening as a tool for health promotion. The early identification of health issues in all children and the follow-up on referrals led to the implementation of corrective measures that facilitated learning. This follow-up involved numerous professionals and helped identify and remove certain barriers to access to care. National standardization of professional practices and the digitization of health data would enhance the epidemiological effectiveness of this policy.