The adipose-derived stromal vascular fraction (SVF) represents a rich source of mesenchymal cells, potentially able to differentiate into adipocytes, chondrocytes, osteoblasts, myocytes, cardiomyocytes, hepatocytes, and neuronal, epithelial, and endothelial cells. These cells are ideal candidates for use in regenerative medicine, tissue engineering, including gene therapy, and cell replacement cancer therapies. In this work, we aimed to the optimization of the adipose SVF-based therapy, and the effect of the collection site, surgical procedure, and tissue processing techniques on SVF yield was evaluated in terms of cell recovery and live cells, taking into account the effect of gender, age, and body mass index. Adipose tissue samples were recovered from 125 informed subjects (37 males and 88 females; mean age: 51.31 years; range: 15–87 years), and digested in different condition with collagenase. A multivariate linear model put in evidence that in males the best collection site in terms of yield is located in the abdomen, whereas in females the biopsy region do not influence cell recovery; the collection technique, the age, and the body mass index of donor seem not to influence the cell yield. The tissue-processing procedures strongly modify the yield and the vitality of cells: a collagenase concentration of 0.2% and a digestion time of 1 h could be chosen as the best operating conditions.