Protoplast culture following polyethylene glycol (PEG)-induced fusion resulted in the regeneration of somatic hybrid plants from the following combinations: `Succari' sweet orange (C. sinensis L. Osbeck) + Severinia disticha; `Hamlin' sweet orange (C. sinensisj + S. disticha: `Valencia' sweet orange (C. sinesis) + S. disticha; `Nova' tangelo (C. reticulata hybrid) + S. disticha; `Succari' sweet orange + S. buxifolia; `Nova' tangelo + Citropsis gilletiana; and `Succari' sweet orange + Atlantia ceylanica. `Succari', `Hamlin', `Valencia', and `Nova' protoplasts were Isolated from ovule-derived embryogenic callus and/or suspension cultures whereas protoplasts of S. disticha, S. buxifolia, C. gilletiana, and A. ceylanica were isolated from leaves of potted trees in a greenhouse. Plants were regenerated via somatic embryogenesis and somatic hybrids were identified on the basis of leaf morphology. Electrophoretic analysis of isozyme banding patterns and root tip chromosome counts are being performed. Somatic hybrids with S. disticha are apparently weak whereas the other somatic hybrid plants with S. buxifolia, C. gilletiana, and A. ceylanica exhibit adequate vigor. These are more examples that the the techique of protoplast fusion can be an important tool in overcoming barriers to hybridization of sexually incompatible species.