Background Autologous fat transplantation is a promising technique for soft tissue augmentation. However, the longterm maintenance of fat grafts remains unpredictable. Based on Peer's cell theory, techniques that cause less cellular damage will optimize graft integration. Water jet-assisted liposuction (WAL) was introduced as a gentle and efficient technique for harvesting a large volume of fat in a short period of time. In this study, we evaluated the viability and function of adipocytes and preadipocytes harvested using WAL and compared this with the Coleman technique. Methods Eleven patients were enrolled in this study. Fat grafts were harvested using WAL from one limb and the Coleman technique from the other limb. The lipoaspirates were compared based on the following analyses: trypan blue vital staining for viable adipocyte and preadipocyte counts, glycerol-3-phophatase dehydrogenase assay for adipocyte function, histological examination, and speed of fat harvest.