We propose to survey an area of 1/2 square degrees of the Bar in the Large Magellanic Cloud with ISOCAM, in the LW10 (12 microns) and LW1 (4-5 microns) filters. The total time requested is 8h36mn. Our scientific goal is to estimate the mass-loss rates of a statistically complete sample of AGB stars, covering the different chemical types and the whole range of mass-loss rates, and to compare the results with current theories on evolution of AGB stars. This has never been done, and cannot be done in our Galaxy because distances are not known. This mini-survey will be complemented by IJK' observations of DENIS, and by the ISO Central Program proposal of N.Trams et al. at longer wavelengths. As the distance of the LMC is known, these data will allow to determine the luminosities and mass- loss rates of AGB stars. Ground-based instruments are not sensitive enough to achieve our goal; an accurate determination of the luminosities of AGB stars requires data in this wavelength range; two bands are necessary to identify them, and to remove foreground stars. Due to observational biases and limitations, most AGB stars in the LMC with mass-loss rates ranging between 1E-6 and 1E-5 Mo/yr have not been discovered yet. As a consequence, the only possible strategy is to make a survey. Going up to a level of 4 mJy at 12 microns, we will detect all the stars in the thermal pulses stage on the AGB, wheter they are losing mass or not. We expect a total of about 1000 AGB stars in 1/2 square degree.