This paper presents the realization of a fault tolerance technique for a dynamically reconfigurable array of programmable cells. The three parts of the technique, fault detection, fault reconfiguration, and fault recovery, are implemented completely in hardware and form a self-contained system. Each of the parts can be exchanged by an alternative implementation without affecting the remaining parts too much, thus making the concept adaptable to different reconfigurable circuits. A hardware realization for the core mechanism is discussed and a prototypical design of a field-programmable gate array implementing the complete system is described. The technological development towards nanoscale feature sizes and the growing influence of deep-submicrometer effects will result in an inherent unreliability of the individual components of future circuit implementations and a higher vulnerability towards external influences. The technique discussed can be used to exploit dynamic reconfiguration capabilities of programmable arrays to alleviate system vulnerability towards these effects and thus to enhance their overall reliability.