This is the first of three reports on the Supportive Services Demonstration for Elderly Households in the U.S. Department of Housing and Urban Development’s (HUD)-Assisted Multifamily Housing. HUD sponsored this test of the impact of the Integrated Wellness in Supportive Housing (IWISH) model on the healthcare utilization and housing stability of low-income adults aged 62 and older. This report documents the baseline characteristics of affected residents and describes how most properties made progress enrolling residents and conducting health and wellness assessments in the first 18 months of the demonstration.