Extensive research draws attention to the causes and consequences of homelessness. Missing from this literature is a holistic assessment of the conditions and characteristics of optimum shelter service delivery. This exploratory study reports results from a qualitative study conducted mid 2006 through early 2008 consisting of 1:1 key informant interviews with 50 expert practitioners in North America and the United Kingdom who are employed in, and/or experts on, homelessness services or urban planning and design. Findings show that success in service delivery is largely defined by an overlap of several characteristics associated with three major themes. The first theme, systemic characteristics of a shelter, includes such characteristics as shelter programs, shelter management, and shelter attention to client dignity and safety. The second theme, community relationships, includes perceptions of the homeless and of public safety, the challenges of NIMBYism, & positive community involvement. The third theme, the built environment, includes shelter congruency, shelter size, shelter location and accessibility, and a shelter's community impact. The analysis of findings provides evidence of particularly important precedents that could lead to potential improvements in service delivery, and to inform future research agendas