Abstract
I summarize the current status of the determinations of galaxy masses based on population synthesis models at ages at which the TP-AGB stars dominate the NIR luminosity (≈1). Mass estimates of galaxies with dominant stellar populations in this age range thus depend critically on the treatment of TP-AGB stars in population synthesis models. Here I present some preliminary results from Charlot, S., & Bruzual, G. (2011, in preparation) and a list of weak points in the modeling of stellar populations that hopefully will be improved in the near future.