CHSE-214 was incubated only at IS, 20 and 2S'C, because they do not survive at higher temperatures. The mammalian cells were incubated at 37, 30 and 2S'C but not at lower temperatures. After the a9sorption period, the remaining inocula were decanted. The monolayers were incubated with S ml of EMEM without serum at the corresponding temperature. Uninoculated flasks of each cell line were incubated at the different temperatures, and used as controls. The flasks were observed daily to determine the time to appearance of cytopathic effect (CPE) and the time for total destruction of the monolayer. After a maximum incubation period of 4S days, flasks with no CPE were rejected. The fish rotaviruses were not able to produce CPE in either of the two mamalian lines or in FHM cells. As shown in Table 1, all the viruses produced CPE at lS'C in CHSE-214, EPC and BB cells, and at 20'C in CHSE. No CPE was detected at any higher temperature. Table 1 shows that the appearance of CPE was rapid in CHSE-214 line with total destruction of the monolayer in' 3 weeks or less at both IS' and 20·C. In contrast although all rotaviruses replicated in EPC line, the development of the CPE was slow, taking at least one month. In BB, only SBR and SRV produced CPE in the first week postinfection' at lS'C, while the altlantic salmon rotavirus (ASR) was not able to grow in that cell line. These results indicate that the CHSE214 is the most useful cell line for the culture of fish rotaviruses at IS and 20·C. The different behaviour of these cell lines to support the growth of the five viruses could be based upon differences in the ability to adsorb on the cells and/or in their capacity to replicate in them.