A unified continuum approach to brittle and fatigue damage is presented. A scalar variable is used to represent the damage state. General forms of the constitutive equations are established on a thermodynamic basis. Specific evolution laws are postulated and used to illustrate the capacity of the model. The governing equations are solved numerically. The computational effort is reduced by the application of an adaptive stepsize selection procedure for the integration of the rate equations and by uncoupling the constitutive equations. The response of a plate with an induced crack subjected to periodic loading is studied.