Electroporation has been adapted for the transfer of macromolecules into various cells of tissues in vivo. Although mature adipocytes constitute less than 20% of cells residing in adipose tissue, we have found that fat cells are susceptible to selective electrotransfer of plasmid DNA owing to their large size relative to other cells in the tissue. The procedures detailed here permit electrotransfer of plasmid DNA into mature fat cells with greater than 99% selectivity over other cells in the tissue. This “adiporation” technique can be used to image the subcellular targeting of fluorescent bioreporter molecules and to manipulate the activity of specific pathways within adipocytes in situ.