Adipose-derived stem cells (ADSCs) are the most commonly used type of mesenchymal stem cell (MSC) in the clinic. ADSCs have some advantages in transplantation compared with MSCs from bone marrow and umbilical cord blood. ADSCs produce important growth factors for wound healing, modulate the immune system, decrease inflammation, and home to injured tissues. In particular, ADSC extraction from adipose tissue is a simple procedure with minimum invasiveness. Therefore, ADSCs have been evaluated in clinical trials and used in the treatment of many diseases. To date, ADSC transplantation has been approved in some countries to treat medical complications such as perianal pistula and osteoarthritis. This review provides an overview of the applications and future challenges of the use of ADSCs in clinical settings.