['Food insecurity, or the uncertain availability of nutritionally adequate, safe foods, has been associated with poor HIV outcomes. There are few data on the extent to which food insecurity impacts patterns of health-care utilization among HIV-infected individuals.', 'We examined whether food insecurity was associated with hospitalizations, Emergency Department (ED) visits, and non-ED outpatient visits.', 'HIV-infected, homeless and marginally housed individuals participating in the San Francisco Research on Access to Care in the Homeless (REACH) cohort underwent quarterly structured interviews and blood draws. We measured food insecurity with the validated Household Food Insecurity Access Scale, and categorized participants as food secure, mild/moderately food insecure, and severely food insecure. Primary outcomes were: (1) any hospitalizations, (2) any ED visits, and (3) any non-ED outpatient visits. Generalized estimating equations were used to estimate model parameters, adjusting for socio-demographic (age, sex, ethnicity, education, income, housing status, health insurance) and clinical variables (CD4 nadir, time on antiretroviral therapy, depression, and illicit drug use).', 'Beginning in November 2007, 347 persons were followed for a median of 2 years. Fifty-six percent of participants were food insecure at enrollment. Compared with food-secure persons, those with severe food insecurity had increased odds of hospitalizations [adjusted odds ratio (AOR)\u2009=\u20092.16, 95 % confidence interval (CI)\u2009=\u20091.50-3.09] and ED visits (AOR\u2009=\u20091.71, 95 % CI\u2009=\u20091.06-2.30). While the odds of an outpatient visit were 41 % higher for severely food insecure individuals, the effect was not statistically significant (AOR\u2009=\u20091.41, 95 % CI\u2009=\u20090.99-2.01). Mild/moderate food insecurity was also associated with increased hospitalizations (AOR\u2009=\u20091.56, 95 % CI\u2009=\u20091.06-2.30), ED visits (AOR\u2009=\u20091.57, 95 % CI\u2009=\u20091.22-2.03), and outpatient visits (AOR\u2009=\u20091.68, 95 % CI\u2009=\u20091.20-2.17).'] Is food insecurity associated with greater acute care utilization among HIV-infected homeless and marginally housed individuals in San Francisco?