To assess the feasibility of advice to injection drug users (IDUs) to use a sterile syringe for each injection, we examined sources of syringes, syringe use and reuse, and barriers to and facilitators of compliance with the one-time use of syringes by active IDUs in seven U.S. metropolitan areas. Brief, interviewer-administered surveys were completed by 593 active IDUs, defined as injection reported within the past 90 days, in seven U.S. metropolitan areas characterized by various restrictions on syringe acquisition and possession. Most of the IDUs interviewed were male (69%) and African American (74%). Overall, only 23% obtained the most recently used syringe from a reliable source of sterile syringes (i.e., pharmacy or syringe exchange program [SEP]). The median number of injections per most recently used syringe was 3 (mean=5.2); 21% used the syringe only once. IDUs were more likely to have used a reliable source for obtaining their most recent syringe in cities with a SEP (odds ratio [OR]=5.3; 95% confidence interval [CI] 3.3-8.5) or without restrictive paraphernalia laws (OR=0.1; 95% CI 0.1-0.3). To facilitate one-time use of sterile syringes, IDUs recommended the provision of free syringes (50.3%), access to a SEP (38.1%), and access to pharmacy purchase of syringes (24.0%). Restrictions on syringe availability and the beliefs and practices of IDUs are barriers to the public health recommendation of one-time use of sterile syringes for IDUs who cannot stop injecting. Increased access to legal, inexpensive sterile syringes and education about the merits of one-time use are needed.