For the past few years, consumer products such as computers, mobile phones, and cameras have drastically decreased in size and their functionalities have increased. In addition, mini-invasive techniques in surgery have led to a growing need for small, highly reliable components that can go through arteries or veins. In general, there are nearly no highly technological products that do not benefit from miniaturization. However, one cannot simply scale down electrical or mechanical components from "macroscale" because physical forces do not scale down at the same amplitude. Therefore, the efficiency of actuators depends on their size. Consequently, there is a need for new actuating technologies adapted to the microworld that can replace usual actuators such as electromagnetic motors. Among these technologies, smart materials such as piezoceramics, magnetostrictive, electrostrictive, and shape-memory materials are of particular interest. This article describes the use of shape-memory alloys (SMA) for microengineering applications.A brief description of SMA properties is given. Some usual design principles are addressed. A literature survey and a concept of monolithic microdevices concludes the article.