Since 1960, more than 100,000 Starr-Edwards prostheses have been inserted. In conjunction with a continuing program of bioengineering improvements which has alleviated many problems, certain complications have been associated with specific valve models. Thus, it is often useful to identify the valve model in the absence of a previous operative record. The various models of Starr-Edwards prostheses can be differentiated from plain chest roentgenograms. The identifying roentgenographic characteristics are described in this report.