Study of diseases affecting commercially-important molluscan species has been hindered by the lack of suitable cell culture systems. In vitro cultivation of marine molluscan cells has been attempted by several investigators but with limited success. To date, only one molluscan cell line, that of the freshwater snail, Biomphalaria glabrata, has been successfully cultured. Although primary cultures have been established from a number of bivalves. In some cases being maintained for several months, no continuously-dividing cell line has yet been reported. This research area is likely to be increasingly important to workers involved in emerging fields such as toxicity testing and the monitoring of water quality as well as in screening and culturing of shellfish viruses and other microbiological parasites. This paper reviews the current literature in the field of molluscan cell culture and describes methods used in such work.