Voice disguise involves deliberately changing one’s voice to conceal their identity. It is most often associated with crimes such as kidnapping, fraud, etc. In addition to being a general problem in the world of crime, it is a particular one in the area of Speaker Identification (SI) and for the following reasons: (1) There appears to be no limit on human ingenuity in the types of disguise that can be employed. (2) While there are unlimited ways to disguise speech, there seem to be far too few studies to provide useful information about it. (3) Further these studies are narrow in scope. This can be attributed to the extensive number of variables (type of disguise, familiarity with the speaker, language, dialect, etc.) and the need for their control. (4) Because of these limitations, a great deal more needs to be known about the major types of disguise and the ones detrimental to SI. Thus, the numerous issues plaguing voice disguise must be addressed systematically through an integrated research program. A review of their nature, the research needed and the reasons for conducting the program will be discussed. Data from a sample experiment of this type will be presented.