<h3>Importance</h3> Scattered-site housing with Intensive Case Management (ICM) may be an appropriate and less-costly option for homeless adults with mental illness who do not require the treatment intensity of Assertive Community Treatment. <h3>Objective</h3> To examine the effect of scattered-site housing with ICM services on housing stability and generic quality of life among homeless adults with mental illness and moderate support needs for mental health services. <h3>Design, Setting, and Participants</h3> The At Home/Chez Soi project was an unblinded, randomized trial. From October 2009 to July 2011, participants (N = 1198) were recruited in 4 Canadian cities (Vancouver, Winnipeg, Toronto, and Montreal), randomized to the intervention group (n = 689) or usual care group (n = 509), and followed up for 24 months. <h3>Interventions</h3> The intervention consisted of scattered-site housing (using rent supplements) and off-site ICM services. The usual care group had access to existing housing and support services in their communities. <h3>Main Outcomes and Measures</h3> The primary outcome was the percentage of days stably housed during the 24-month period following randomization. The secondary outcome was generic quality of life, assessed by a EuroQoL 5 Dimensions (EQ-5D) health questionnaire. <h3>Results</h3> During the 24 months after randomization, the adjusted percentage of days stably housed was higher among the intervention group than the usual care group, although adjusted mean differences varied across study cities (Site A: 417.3 of 683.0 days [62.7%] for the intervention group vs 189.2 of 621.6 days [29.7%] for the usual care group, mean difference [MD], 33.0% [95% CI, 26.2% to 39.8%]; Site B: 491.5 of 653.4 days [73.2%] for the intervention group vs 157.0 of 606.8 [23.6%] for the usual care group, MD, 49.5% [95% CI, 41.1% to 58.0%]; Site C: 506.7 of 658.1 days [74.4%] for the intervention group vs 255.2 of 626.2 days (38.8%) for the usual care group, MD, 35.6% [95% CI, 29.4% to 41.8%]; Site D: 520.4 of 651.5 days [77.2%] for the intervention group vs 223.1 of 649.1 for the usual care group [31.8%], MD, 45.3% [95% CI, 38.2% to 52.2%];<i>P</i>&lt;.001 for interaction). The mean change of the EQ-5D score from baseline to 24 months among the intervention group was not statistically different from the usual care group (60.5 [95% CI, 58.6 to 62.5] at baseline and 67.2 [95% CI, 65.2 to 69.1] at 24 months for the intervention group vs 62.1 [95% CI, 59.9 to 64.4] at baseline and 68.6 [95% CI, 66.3 to 71.0] at 24 months for the usual care group, difference in mean changes, 0.10 [95% CI, −2.92 to 3.13],<i>P</i>=.95). <h3>Conclusions and Relevance</h3> Among homeless adults with mental illness in 4 Canadian cities, scattered site housing with ICM services compared with usual access to existing housing and community services resulted in increased housing stability over 24 months, but did not improve generic quality of life. <h3>Trial Registration</h3> isrctn.org Identifier:ISRCTN42520374

Effect of Scattered-Site Housing Using Rent Supplements and Intensive Case Management on Housing Stability Among Homeless Adults With Mental Illness