<span lang="en">This paper considers the problem of provisioning services in proactive ad hoc networks. Our proposal consists in a service discovery mechanism, integrated on the proactive OLSR (Optimized Link State Routing) protocol. We define a new message type into OLSR called Service Discovery Message (SDM) for advertising and discovering services. The advertisement frequency and advertisement lifetime are usercontrolled parameters, so that they can be modified depending on the user requirements. Each node maintains a service cache to store information about services discovered via advertisements. We also present simulation results that demonstrate that the service discovery mechanism defined here, introduces insignificant packet overhead compared to the basis OLSR protocol.</span>