HIV infection has become a chronic condition that for most persons can be effectively managed with regular monitoring and appropriate medical care. However, many HIV positive persons remain unconnected to medical care or have less optimal patterns of health care utilization than recommended by good clinical practice standards. This paper investigates housing status as a contextual factor affecting access and maintenance in appropriate HIV medical care. Data provided from 5,881 interviews conducted from 1994 to 2006 with a representative sample of 1,661 persons living with HIV/AIDS in New York City demonstrated a strong and consistent relationship between housing need and remaining outside of or marginal to HIV medical care. In contrast, housing assistance increased access and retention in medical care and appropriate treatment. The relationship between housing and medical care outcomes remain controlling for client demographics, health status, insurance coverage, co-occurring mental illness, and problem drug use and the receipt of supportive services to address co-occurring conditions. Findings provide strong evidence that housing needs are a significant barrier to consistent, appropriate HIV medical care, and that receipt of housing assistance has an independent, direct impact on improved medical care outcomes.