Purpose: Syringe aspiration (SA) is a commonly used method for harvesting adipose tissue for autologous fat grafting. Water-jet assisted liposuction (WAL) is becoming more widely used and is considered a more gentle method for removing adipose tissue, though this observation lacks supporting data. Differences in tissue quality between these WAL and SA acquisition methods were determined by assessing the biologic properties of the mature fat cells, and the stromal vascular fraction cells found within or loosely attached to the adipose tissue. Methods: Tissue was collected by both procedures on opposite sides of the same bilateral depot (N=5). Adipose tissue quality was evaluated by the functional lipolysis assay. Tissue from both harvesting methods were processed with the Celution® 800/CRS device (Cytori Therapeutics, CA) and the nucleated cell output was evaluated by cell yield, viability, flow cytometry and clonogenic assays. For loosely attached cells and the cells lost in the wetting solution, the number of viable cells was determined. Results: Adipose harvested by both methods had comparable lipolysis activity. In addition, similar numbers of viable adipose-derived stem and regenerative cells (ADRCs) were obtained from intact tissues harvested by both methods. Significantly more viable loose cells were collected from SA harvested samples (27.53±10.95 x104, with 91.42±6.55% viability) compared to WAL harvested tissue (2.26±1.59x104, with 62.36±18.30% viability, both p<0.001). By CFU-F assay the total number of ADRCs from SA samples (1.90±0.21%) was significantly higher than that of WAL samples (1.12±0.23%, p<0.001). Conclusion: The health of intact mature adipose tissue obtained by both harvest methods is comparable. Furthermore, the viability, concentration within the intact tissue parcels, and the molecular phenotype of stromal vascular cells obtained from this tissue is also comparable. However, the use of WAL resulted in significantly less loosely adherent cells remaining attached to the adipose tissue after processing. As a result more clonogenic adipose stem and regenerative cells were found in the SA harvested graft. Therefore, while WAL harvested graft tissue appears enriched in regard to mature fat cells; a ramification of this concentration and purification may be the significant loss of ADRCs. Further studies in vivo are warranted.