The emergence of PET andMRI as a hybridmodality has generated widespread interest in the technology and techniques. Although adoption and use are unlikely to be as expansive as for PET and CT hybrid systems, PET/MRI is an important modality that requires broad insight for nuclear medicine professions generally and deeper insight for those engaged in PET/MRI practice. This article provides insight into the considerations and challenges associated with establishing a PET/MRI facility. Each clinical site will present unique requisites for establishing a PET/MRI facility, and indeed, each PET/MRI vendor will have specific site requirements. Nonetheless, this article provides general insight into common considerations but should not be considered exhaustive. Here, development of the facility, staffing of the facility, and implications of both radiation and MRI safety are considered from the context of facility design. Given that the nature of PET is well established among the readership of this journal, the article provides an emphasis on MRI factors. This article is the first in a 4-part integrated series sponsored by the PET/MR and Publication Committees of the Society of Nuclear Medicine and Molecular Imaging-Technologist Section. In the subsequent 3 parts, PET/MRI will be explored on the basis of technology principles (part 2), protocols and procedures (part 3), and applications and clinical cases (part 4).