This book constitutes the refereed proceedings of the Second International Workshop on Quality of Service in Multiservice IP Networks, Qo S-IP 2003, held in Milano, Italy in February 2003. The 53 revised full papers presented together with an invited paper were carefully reviewed and selected from 97 submissions. The papers are organized in topical sections on analytical models, Qo S routing, measurements and experimental results, Qo S below IP, end-to-end Qo S in IP networks, Qo S multicast, optical networks, reconfigurable protocols and networks, provision of multimedia services, Qo S in multidomain networks, congestion and admission control, and architectures and protocols for Qo S provision.