Technical Abstract: Clonal cultures of pig-derived mature adipocytes are capable of dedifferentiating and forming proliferative-competent progeny cells in vitro. Initial lipid processing, is different to that observed in cultures of beef-derived adipocytes. Mature pig adipocytes extrude lipid before proliferation, whereas beef-derived adipocytes symmetrically, or asymmetrically, divide without expelling lipid. These observations suggest that dedifferentiation of mature adipocytes relies on species-specific mechanisms, or that different culture conditions are required for pig-derived adipocytes to dedifferentiate in a manner similar to beef adipocytes. This in vitro system will aid in our understanding of lipid metabolism, regulation of single cells, processes involved in dedifferentiation of cells, and/or characteristics of putative stem cells residing in adipose tissue.