Internet-based support groups are a rapidly growing segment of mutual aid programs for individuals with chronic illnesses and other challenges. Previous studies have informed us about the content of online exchanges between support group members, but we know little about the ability of these interventions to change participants' perceptions of support. A randomized trial of 160 adult Type 2 diabetes patients provided novice Internet users with computers and Internet access to 1 of 4 conditions: (a) diabetes information only, (b) a personal self-management coach, (c) a social support intervention, or (d) a personal self-management coach and the support intervention. After 3 months, individuals in the 2 support conditions reported significant increases in support on a diabetes-specific support measure and a general support scale. Participants' age was significantly related to change in social support, but intervention effects were still significant after accounting for this relationship. This report is a critical first step in evaluating the long-term effects of Internet-based support for diabetes self-management. The discussion identifies directions for future research.