Objective: To compare the Household Food Insecurity Access Scale (HFIAS), the US Food Security Survey Module (US FSSM) and a modified version of the US FSSM in which references to buying food were changed to references to getting food, in terms of their classification of food security levels among homeless individuals, and to determine which of these instruments was most preferred by homeless individuals.

Design: A cross-sectional survey.

Setting: Recruitment of participants took place at seven shelters and from three drop-in programmes that serve homeless individuals in Toronto, Canada.

Subjects: Fifty individuals who were ≥18 years of age, able to communicate in English and currently homeless.

Results: The modified US FSSM assigned 20 % of participants to a lower ordinal food security category compared with the US FSSM, and only 8 % to a higher food security category. The HFIAS assigned 30 % of participants to a lower food security category compared with either the US FSSM or the modified US FSSM, and only 10–16 % of participants to a higher food security category. When asked to compare all three instruments, the majority of respondents (62 %) selected the HFIAS as the best instrument for people who are homeless.

Conclusions: A majority of homeless individuals selected the HFIAS as the best food security instrument for people who are homeless. Our findings suggest that the HFIAS is a more appropriate instrument than the US FSSM for measuring food security in the homeless population.