Accelerated tests are conducted at various stages of the product life cycle. When accelerated life tests yield few or no failures at low stress levels, it is difficult or impossible to estimate reliability at the design stress level. In such situations, accelerated degradation tests may be used. This presentation introduces accelerated degradation test methods, degradation models, estimation of model parameters, relationships between degradation and reliability, and estimation of reliability at the design stress level. Several practical examples are presented.