  Evolutionary synthesis models for Tidal Dwarf Galaxies (TDGs) are presented
that allow to have varying proportions of young stars formed in the
merger-induced starburst and of stars from the merging spirals' disks.
Comparing model grids with observational data (see e.g. P.-A. Duc this
conference for a review) we try to identify the present evolutionary state of
TDGs. The influence of their specific metallicities as well as of the gaseous
emission of actively star forming TDGs on their luminosity and colour evolution
are studied.
