Service matchmaking is an important process in the operation of Service-Oriented Architecture (SOA) based systems. In this process, information from both service providers and requestors are used. How to protect the privacy of participating parties during the matchmaking process imposes a challenge. In this paper, a privacypreserving service matchmaking approach is presented to support semantic-based service matchmaking and avoid privacy leakages to untrusted parties. The approach uses situation-aware access control (SA-AC) mechanism to ensure the appropriate disclosure and use of private information by modeling, specifying and enforcing SA-AC policies. It provides an owner-centric mechanism for both service providers and requestors in SOA-based systems to protect their private information during service matchmaking. Keyword: Service-oriented architecture, SOA-based systems, service matchmaking, privacy-preserving, situationaware access control.