This paper discusses the testing for retentivity of non-volatile memories. The physics associated with the reliable production of various non-volatile data storage devices has long been a topic of debate. The ability to reliably produce devices which endure erase/write cycling and retain data for extended periods of time has been questionable. Recent improvements in IC processing has given rise to claims of enhancements in both of these areas. Non-volatile memories are attractive in many automotive electronic applications where battery backup is neither convenient or feasible, but because of reliability concerns they have not found their way into critical applications. In applications like odometer or emission control calibrations it is imperative that memory retention is assured.In order to verify the reliability of the various available non-volatile memory devices, an accelerated test program was instituted. The two primary concerns of the testing were to verify the devices ability to retain data over time and also their ability to accept erase/write cycles after extended periods of time. This paper presents the test plan, test results, and conclusions that can be drawn from the tests.