This volume contains the papers presented at the workshop on "Designing Correct Circuits", jointly organized by the Universities of Oxford and Glasgow, and held in Oxford on 26-28 September 1990. There is a growing interest in the application of software engineering techniques to hardware design. As the complexity of hardware systems grows, and as the cost both in money and time of making design errors becomes more apparent, so there is an eagerness to build on the success of mathematical techniques in program development. The authors consider the application of mathematics to hardware design at several different levels of abstraction and present a good cross-section of current work developing and applying formal methods in circuit design.