After the thalidomide epidemic in the early 1960s, many jurisdictions developed congenital anomaly surveillance systems. Congenital limb deficiencies can act as indicators of potential teratogens. The classification of congenital limb deficiencies is essential to determine the precise cause or causes of this anomaly. This article describes the different terminology and classification that have been used over time and the need for a consensus. While there are a variety of studies examining the epidemiology and etiology of congenital limb deficiencies, there is an inconsistent use of terminology and classification which makes comparisons between studies challenging. © 2016 Wiley Periodicals, Inc.