This study reports the characterization of 11 plants regenerated from electrically fused protoplasts between Populus alba and Alnus firma. Growth characteristics of five regenerated plants (AP-1–AP-5) in terms of shoot height and leaf color showed small differences compared with those of P. alba grown in pots, and showed no difference in shoot height and diameter compared with those grown in nursery field. There was also no difference in the RAPD pattern between the plants regenerated from interfamilial protoplast fusion and P. alba. In contrast, the lately regenerated plants (AP-6–AP-11) grown in pots showed a marked difference in leaf morphology and RAPD pattern. There was a variation in the ratio of longitudinal to transverse length of leaves among the 11 plants from interfamilial fusions compared with that of protoclones and intraspecific fused protoplasts of P. alba.