BACKGROUND: This preclinical study evaluated benchtop/in vitro properties and fat viability and activity of grafts processed using the REVOLVE ENVI 600 system compared with decantation and evaluated properties of REVOLVE ENVI waste. METHODS: Lipoaspirate from six donors was processed using REVOLVE ENVI or decantation. The composition of each graft, hematocrit/red blood cell content, fat particle size/macrostructure, viable adipocyte count, and adipocyte activity were analyzed. Stromal vascular fraction was analyzed for viable progenitor cell count and colony-forming units. RESULTS: REVOLVE ENVI grafts had a higher mean (±SD) fat content at 85.6% ± 6.1% than decanted grafts at 72.1% ± 4.0% (P < 0.001), with negligible free oil (0.4% ± 1.1%) and cellular debris (<0.1%), whereas REVOLVE ENVI waste contained primarily aqueous fluid (91.0% ± 2.2%) with negligible viable fat. REVOLVE ENVI grafts had significantly lower hematocrit levels (P < 0.001) and contained significantly more large fat globules (P < 0.001) than decanted grafts or REVOLVE ENVI waste. The percentage of tissue particles of more than 1000 µm was highest for REVOLVE ENVI grafts at 61.6% ± 9.2% (decantation: 52.5% ± 13.4%; REVOLVE ENVI waste: 0.49% ± 1.50%), and the percentage of particles less than 200 µm was lowest for REVOLVE ENVI grafts at 15.7% ± 2.6% (decantation: 32.2% ± 8.9%; REVOLVE ENVI waste: 97.9% ± 4.5%). REVOLVE ENVI grafts contained 145.2% ± 36.0% more viable adipocytes, 145.7% ± 46.2% greater activity, 195.5% ± 104.2% more progenitors in SVF, and 363.5% ± 161.2% more SVF colony-forming units than decanted grafts. CONCLUSION: Fat grafts processed using REVOLVE ENVI demonstrated greater viability and activity than decanted grafts in vitro.