Shortly after the introduction of the earned income supplement (RSA), the non-take-up of this benefit was assessed using a special survey carried out in 2010-2011 by the Department for the Organisation of Research, Studies and Statistics (DARES), which is part of the Ministry of Labour, Employment and Economic Inclusion. The advantage of this type of operation is that measuring non-take-up can be combined with in-depth analysis of its causes and underlying behaviour. However, this is a costly operation that can only be done on an ad-hoc basis and is subject to measurement difficulties. For a less costly and more regular measurement of non-take-up, the use of survey data on resources in the general population, produced periodically and backed by a tax-benefit microsimulation model, seems more appropriate. Based on these tools, this DREES report proposes a method for estimating the non-take-up of two benefits: the earned income supplement and the employment bonus (PA). This work shows that it is possible to regularly measure the non-take-up of RSA. In 2018, one third of RSA-eligible households would have been non-recipients each quarter, and one fifth would have been for pro-longed periods throughout the year. The unpaid sums corresponding to the non-take-up of RSA would reach €750 million, per quarter, in the area covered5. However, additional data, which is currently unavailable, is still needed to estimate the non-take-up of the PA.