In a previous paper, Saccharomyces cerevisiae LBG H620 and DSM 2155 were compared regarding their ability to float. LBG H620 did not float at all; DMS 2155 floated excellently. The investigations of the cells’ surface properties indicated that yeast LBG H620 has a high surface hydrophilicity and a high electrokinetic potential; yeast DSM 2155 possesses high hydrophobicity and a low electrokinetic potential [Tybussek et al. (1994) J Appl Microbiol Biotechnol 41:13-22]. In the present paper, the morphologies of these two yeast strains are compared. Strain LBG H620 formed only single or budding cells, strain DSM 2155 formed cell aggregates, their size depending on the cultivation conditions : in the presence of adequate substrate concentration cell aggregates were formed, and during substrate limitation single cells dominated. During respiratory growth rather small spherical aggregates and during respiratory/fermentative growth long-string aggregates were observed.