2373 20160701171704.0 ASTROimport-530 Lampens, P. 1997 On the Mass-Luminosity Relation Hipparcos has provided a lot of new data about double stars including accurate relative positions, magnitudes of the components and parallaxes. Some 170 visual binaries with relatively well known orbits and accurate parallaxes have been selected in order to determine or improve their component masses by making use of these new data. Additional colour information allowed us to obtain the conversion between Hipparcos and bolometric magnitudes. By combining the newly determined parallaxes and differential magnitudes with available ground-based colours and spectral types, we were able to derive component luminosities for our sample of visual binaries. This increase in stellar mass material allows to re-assess the currently adopted mass-luminosity relation (MLR) in the range 0 M_(bol) 7 mag. Kovalevsky, J. Froeschle, M. Ruymaekers, G. Hipparcos - Venice '97 402 1997 421-424 http://esoads.eso.org/abs/1997ESASP.402..421L published in NONREF