This volume contains papers from the OOPSLA-93 Conference Workshop on Security for Object-Oriented Systems, held in Washington DC, USA, on 26 September 1993. The workshop addressed the issue of how to introduce an acceptable level of security into object-oriented systems, as the use of such systems becomes increasingly widespread. The topic is approached from two different, but complementary, viewpoints: the incorporation of security into object-oriented systems, and the use of object-oriented design and modelling techniques for designing secure applications. The papers cover a variety of issues, relating to both mandatory and discretionary security, including security facilities of PCTE, information flow control, the design of multilevel secure data models, and secure database interoperation via role translation. The resulting volume provides a comprehensive overview of current work in this important area of research.