Software for engineering applications has become, during the last few years, a multi-billion pound industry as applications of computer programs are now an essential part of any engineering project. In spite of this, engineer ing software is not always reliable and many fail to produce good solutions. The extent of this problem, which is very costly to the engineering industry, and its consequences, are somewhat hidden because the software industry has not reached the necessary maturity. An engineer needs a long training before being able to design a body for instance. However, to do that, he may use a computer program which has undergone no validation whatsoever and is written by someone without any engineering knowledge. It is imperative to address this problem to ensure that computer codes are properly prepared to provide good solutions, and that they are robust and reliable. This 2nd International Conference on Reliability and Robustness of En gineering Software (RRES 91) was called to address this problem. The meeting was held in Milan, Italy, in April 1991 and was of importance to engineers working in industry who are actively involved with the develop ment of computer codes.