Transient expression of the luciferase gene, under transcriptional control of several heterologous promoters, was obtained in heart primary cell cultures of the Pacific oyster, Crassostrea gigas. Drosophila heat shock protein 70 promoter (hsp70), cytomegalovirus, and simian virus early promoters, controlling the luciferase gene, were tranfected into the cell cultures using liposomes. Two culture media were used to establish primary cell cultures and tested as transfection media. Parameters such as the quantity of DNA and the ratio of DNA to liposome were analyzed to define the best transfection conditions. In oysters, the Drosophila inducible hsp70 promoter behaved in a way similar to that observed in other animal species. Moreover, for this study, hsp70 was more efficient than the cytomegalovirus and simian virus promoters.