This article describes how to obtain isolated cells with no surrounding cell wall by enzymatic digestion of Ectocarpus filaments. The resultant protoplasts are totipotent and regenerate to produce individual algae under appropriate culture conditions. The yield of protoplasts and their capacity to regenerate are highly dependent on the Ectocarpus strain used, the stage of the life cycle, and the culture conditions. The highest yields are obtained with young gametophyte filaments cultivated at low density. The naked, wall-less cells produced by this protocol can be used for several applications, including studies of cell wall regeneration, investigation of the role of the cell wall in determining cell fate, and as a source of naked cells for the development of methods for introducing diverse molecules into the cell.