AbstractFor researchers studying mysticere whales few methods for determining gender or for collecting biochemical and genetic information from unrestrained animals are available. The objective of this study was to develop a reliable method for collecting viable tissue samples for establishing continuous cell cultures from skin biopsies of free‐ranging whales. A method to collect and process these samples is presented. Six of seven skin biopsies from gray whales were established in cell culture. Our results suggest that the viability of the samples is improved by (1) sterile processing in the field, (2) minimizing the time between collection and delivery to the cell culture facility, (3) reducing the concentration of antifungal agent, and (4) placing tissue explants under a coverslip. While the results reported in this paper are based on a small sample size, we believe that if the procedures are followed, they will increase the probability of successfully culturing cetacean tissue. Established cell lines can supply replenishable material from identified whales still living in the wild. These cultures can then be used for determination of sex from karyotypes, and for assessing genetic relationships of cetaceans from inherited protein, chromosomal and DNA polymorphisms. These much needed analytical tools can be used to determine familial and populational relationships, leading to a better understanding of mating systems, stock identification and effective population sizes of wild cetacean