This document is a guide for implementing the Household Food Insecurity Access Scale (HFIAS), which is an adaptation of the approach used to estimate the prevalence of food insecurity in the United States (US) annually. The method is based on the idea that the experience of food insecurity (access) causes predictable reactions and responses that can be captured and quantified through a survey and summarized in a scale. Qualitative research with low-income households in the US provided insight into the following ways that households experience food insecurity (access): Feelings of uncertainty or anxiety over food (situation, resources, or supply); Perceptions that food is of insufficient quantity (for adults and children); Perceptions that food is of insufficient quality (includes aspects of dietary diversity, nutritional adequacy, preference); Reported reductions of food intake (for adults and children); Reported consequences of reduced food intake (for adults and children); and Feelings of shame for resorting to socially unacceptable means to obtain food resources. The intent of this guide is to provide a means for food security programs to easily measure the impact of their programs on the access component of household food insecurity. The rest of the guide is presented as follows: Section 2. Adapting the Questionnaire and Probing lists the generic questions and describes a two-step process to adapt the model questionnaire; Section 3. Interviewer Instructions provides specific instructions to the interviewers; Section 4. presents the Model Questionnaire; and Section 5. Indicator Tabulation Plan describes how the questions can be tabulated to make indicators and provides recommendations for their use and interpretation.(PsycExtra Database Record (c) 2020 APA, all rights reserved)