This study is an extension of our previous paper (Hayashi, M. et al. Polymer, 1998, 39, 299) dealing with the phase separation and structure formation of a polysulfone (PSU)/polyamide (PA) blend as observed by laser scanning confocal microscopy (LSCM) and scanning electron microscopy (SEM). Here we use fluorene-labelled PSU in order to apply fluorescence LSCM for more detailed morphological investigations of the internal structure of a thin film as-cast from solution.