This project investigated the development of primary cell cultures from cod and Atlantic halibut tissues (spleen, heart, optic nerve, brain, liver and tail). By using a range of culture techniques it was concluded that enzymatic disaggregation was the most efficient technique to isolate cells and develop confluent cultures. Almost seventy attempts were made in total to establish a culture. Primary cultures were produced for all organs except liver. Eagle’s Minimal Essential Medium (E-MEM) supplemented with 10% foetal bovine serum was the best all-purpose media of use. Collagen coated tissue culture flasks greatly enhanced attachment of heart cells and poly-Dlysine was beneficial to brain cell attachment. Use of the growth factors epidermal growth factor and endothelial cell growth supplement did not increase the growth of primary cultures but did increase growth in the established cell line CHSE-214 (Chinook salmon embryo). The affect of the chemical mutagen 4-nitroquinoline-N-oxide (4NQO) and two mitogens (calcium ionophore and concanavalin A) on primary cultures was inconclusive. Unusually a few of the heart cultures exhibited spontaneous contractile ability. Unfortunately although the primary cultures of tail, brain and heart were sub-cultured up to four times, they lost their proliferative potential and eventually died.