The methodology of predicting reliability of resonant tunneling diodes (RTD) and non-linear radio signal converters based on them is developed. Reliability of non-linear converters of radio signals is considered on the example of radio frequency identification (RFID) systems with passive tags, the reliability of which is estimated in terms of a parametric failure associated with the I-V characteristics drift of RTDs that are part of the tag rectifier under the influence of external factors beyond the tolerance limits. The methodology of the time to failure of the RFID passive tag power supply system calculation by the criterion of the minimum permissible range is presented. The developed methodology can be used in the design of RFID systems with passive UHF and SHF tags and other non-linear radio signal converters to predict their reliability under specified operating conditions. © 2020, Univelt Inc. All rights reserved.