Although the health impact of patients' trust in physicians has been well documented, less is known about the possible health effects of trust in police or paramedics. Homeless people frequently interact with police officers and paramedics, and these experiences may affect their health and future willingness to seek emergency assistance. We examined homeless people's self-reported interactions with police and paramedics in Toronto, Canada, and their level of trust in these emergency service providers. In a sample of 160 shelter users, 61% had interacted with police in the last 12 months, and 37% had interacted with paramedics (P = .0001). The proportion of subjects who expressed willingness to call police in an emergency was significantly lower than those willing to call paramedics in an emergency (69% vs. 92%, P = .0001). On a Likert scale ranging from a minimum of 0 to a maximum of 5, trust levels were lower in police than in paramedics (median level 3 vs. 5, P = .0001). Among shelter users, 9% (95% confidence interval [CI], 5% to 14%) reported an assault by a police officer in the last year, and 0% (95% CI, 0% to 4%) reported an assault by a paramedic. These findings showed that homeless people have much lower levels of trust in police than paramedics. Reports of negative interactions with police are not uncommon, and homeless people's perceptions of the police may pose a barrier to seeking emergency assistance. Further research is needed for objective characterization of homeless people's interactions with police officers and the potential health implications of low levels of trust in the police.