OBJECTIVE: Research has shown that safer injection facilities (SIFs) are successful at reducing public nuisance and enhancing public health. Since 2007 support for implementation of a SIF in San Francisco has been building. The objective of this study is to assess the acceptability of a SIF among injection drug users (IDUs) in San Francisco. METHODS: IDUs were recruited in San Francisco using targeted sampling and interviewed using a quantitative survey (N=602). We assessed the prevalence of willingness to use a SIF as well as correlates of willingness among this group. RESULTS: Eighty-five percent of IDUs reported that they would use a SIF, three quarters of whom would use it at least 3 days per week. In multivariate analysis, having injected in public and having injected speedballs were associated with intent to use a SIF. The majority of IDUs reported acceptability of many potential rules and regulations of a pilot SIF, except video surveillance, and being required to show identification. CONCLUSIONS: Building on the success of SIFs in various international settings, IDUs in San Francisco appear interested in using a SIF should one be implemented.