Poverty rate calculations are often based on household surveys that exclude some of the groups most vulnerable to poverty such as the homeless. This paper documents the nature of the excluded groups and the quantitative importance of their omission for the Czech Republic. Our study combines European Union Statistics on Income and Living Conditions data for 2011 with information from the 2011 Population Census. Our preferred estimate indicates an increase in the poverty rate by almost one percentage point. The paper contributes to accurately identifying the most vulnerable members of the society, which is essential for setting effective social policies.