The rapid evolution of mass spectrometry in the past 15 years has moved mass spectrometry facilities from the traditional model in which instruments were located in and used for a single department's samples to a distributed model servicing entire universities. In this paper we describe two such shared instrument facilities that have evolved from a base in a single department to facilities that service a broad clientele. The Purdue University Campus-wide Mass Spectrometry Center (CWMSC) is a decentralized facility with multiple sites on campus. The CWMSC is a limited-access facility in which samples are run by service facility personnel in close cooperation with investigators. The Vanderbilt University Mass Spectrometry Research Center (VU-MSRC) is a centralized facility in the medical school that provides services to the university at large. The VU-MSRC is an open-access facility in which users are expected to prepare and analyze their own samples under the guidance of a trained operator. Perhaps the most significant benefit achieved by these models has been the minimization of academic barriers and the resultant intellectual cross-fertilization that has greatly enriched research at institutions where this approach has been adopted. The advantages and limitations of both models are discussed in terms of the traditional academic paradigm of service, research and education.