The response of cells on monolayer chick embryo cultures to infection with Sendai virus was studied. Total infection leads to the death of the cells within 3--5 days postinoculation which permits this system to be considered as lytic. Its significant difference from other systems with the lytic outcome of interaction of non-oncogenic viruses with animal cells consists in marked enhancement of production of proper cellular RNA and proteins in the infected cells and an increase in their division rate preceeding their death.