Satellite altimeter measurements and tide gauge data tied (TTG data) to a global geodetic reference frame by space techniques of positioning will provide in a near future consistent and complementary information to map the mean sea surface (MSS) with a subdecimetric absolute accuracy. Information is consistent because, after standard data processing, both kinds of sea level measurements are given relative to the same geocentric reference ellipsoid. Information is also complementary because: first, satellite altimetry draws a dense sampling pattern of the ocean while TTG mesurements are local; second, the properties of the data errors are very dissimilar in the two techniques. Both kind of sea level measurements are already available in the Mediterranean basin. This study is the first attempt to compute an accurate MSS model with mixed sets of such data. A total inverse method, previously developed to analyze satellite altimetry, is greatly improved in order to recover a full spectrum of the MSS (down to wavelengths λ≂100 km) and to invert rigorously large data sets including consecutive satellite tracks. The MSS solution derived solely from altimetry in the Mediterranean Sea has a formal error of 12 cm under the repeat satellite tracks, up to 30 cm near the coasts, with a further truncation error of 10 cm. Then an analysis of the discrepancy between this solution and TTG data allows us to point out unsuspected inconsistencies in the two data sets which are clearly identified. Nevertheless the usefulness of the TTG data is demonstrated by an estimate of their impact on the error spectrum of the MSS. ¿American Geophysical Union 1990<