Reliability and timely information delivery are mostly concerned in vehicular ad hoc networks (VANETs). In this paper, we propose a link Delay and Reliability constrained QoS routing algorithm (DeReQ) for multimedia communications in VANETs. A new link reliability mathematical model which considers not only the impact of the link duration but also the traffic density is designed. The aim of the DeReQ algorithm is to find a route which is not only reliable but also compliant with delay requirements. We evaluate the performance of DeReQ algorithm through simulations and our simulation results demonstrate that significant performance improvement can be achieved by the combined DeReQ and AODV protocol in comparison to the original AODV protocol, an QoS-extended AODV protocol (AAC), and the location-based routing protocol (LBM).