How states choose to organize and structure their human service agencies determines to a great extent how state human service systems function and how human services are delivered to clients. Little attention has been paid in the social work administration literature to this obviously important issue. Using data from the American Public Human Services Association (APHSA), the authors look at how states have organized their human service systems at three times (1986, 1997, 2006) over a 20-year period. Specifically, the article looks at change and continuity in: 1) the structures and functions of the 50 designated state human service agencies, and (2) preferences for larger centralized umbrella-type agencies versus multiple smaller more specialized human service agencies.