In January 2005, the Massachusetts Department of Public Health announced the designation of approved hospitals as Primary Stroke Services (PSS), based on verifiable demonstration of care pathways for acute ischemic stroke. We investigated the effect of hospital characteristics on participation in the PSS program.In 2003, the Massachusetts Department of Public Health surveyed 72 Massachusetts hospitals on their readiness for PSS designation. Survey results and PSS participation rates were compared among hospitals categorized by bed size (<150 vs. > or =150 beds), rural location, and major teaching hospital status. In answer to 2003 survey questions, smaller hospitals (n = 35) were less likely than larger hospitals to have acute stroke teams (P = 0.01), 24-hour rapid computed tomography scanning and interpretation (P = 0.0006), 24-hour neurosurgery coverage (P = 0.001), and a stroke registry (P = 0.007). Smaller hospitals were less likely to be interested in PSS application in 2003 (P = 0.008), and less likely to be designated PSS when ambulance rerouting to PSS hospitals began in July 2005 (P < 0.0001). Despite this, by December 2005 the majority of Massachusetts hospitals (66/71, 92%) had achieved PSS designation. Smaller hospitals were more likely to use telemedicine to access acute stroke teams (P = 0.003).Many smaller hospitals are able to acquire the resources needed for provision of acute stroke care, despite initial limitations. Innovative strategies, such as telemedicine consultation and transfer agreements, may successfully allow smaller hospitals to satisfy Brain Attack Coalition criteria for primary stroke centers.