Cell lines were established from spleen and heart tissues of a juvenile white sturgeonAcipenser transmontanusand designated WSS-2 and WSH-1, respectively. Isoenzyme analyses of both lines confirmed their host of origin. Both lines were hypotetraploid and possessed micro- and macrochromosomes. The modal chromosome number for the WSS-2 line was 219; the WSH-1 line had a bimodal distribution with modes of 237 and 243. The effects of temperature on growth and susceptibility to selected viral pathogens were examined for the WSS-2 line. Cell replication occurred at 15–30°C, optimum temperature was 25°C. Cell survival was observed after 11 d at 10°C but not at 35°C. The WSS-2line was refractory to infections with channel catfish virus (CCV) and infectious pancreatic necrosis virus (IPNV) but susceptible to infectious hematopoietic necrosis virus (IHNV) and white sturgeon iridovirus (WSIV). The need for cell lines from the host of origin in studies of viral pathogens of fish was demonstrated by the ability of the WSS-2 line to support replication of WSIV.