Dendrimers are very promising molecules as hosts for guest embedding as well as for multiple covalent coupling of dye molecules to their peripheral groups. The use of such dendrimer–dye conjugates as part of a modular carrier system for photodynamic therapy has recently been discussed. Using covalent coupling we accomplished an average loading of 12–13 molecules of pheophorbide a to one diaminobutane poly-propylene-imine dendrimer molecule of the third generation (DAB dendrimer) having a total number of 16 binding sites. This was confirmed with various photophysical measurements and MALDI-mass spectrometry.