The current epidemic of obesity has caused a surge of interest in the study of the mechanisms regulating adipose tissue formation. It has been observed that adipose tissue contains a pool of adult stem cells with multipotent properties, which provide for the physiological cell turnover, and can be isolated and potentially utilized for tissue engineering and regenerative medical applications. These "stromal" cells exhibit pre-adipocyte characteristics, can be isolated from adipose tissue of adult subjects, propagated in vitro, and induced to differentiate into adipocytes. Different populations of multi-potent precursor cells can be isolated from human fat fragments. Thus, adipose precursors cells are a heterogeneous cells population, consisting of fibroblast-like multi-potential stem cells generally termed adipose-derived stem cells (ASCs). In this review, we discuss some aspects of ASCs basic biology, the methodology involved in ASCs isolation and culture, and some implications of ASCs availability for the understanding of metabolic diseases in humans.