Food waste is gaining considerable attention from researchers in terms of its sources, its causes, and its potential effects on the environment, economy, and population health. To date, few instruments exist that allow researchers to measure food waste at the household level in reliable ways. This study aimed to assess the reliability of a newly developed self-assessment tool to measure household food waste, among participants living in Mexico. The survey tool consisted of 11 items which ask participants (N = 22) to estimate the amount of food per category that generally gets thrown away instead of eaten in the average week. Two tests of reliability were conducted, including Cronbach's Alpha for test-retest reliability, and Intra-class Correlation for internal reliability. Results varied across food categories evaluated by individual items. Items related to fresh fruit and bread products did not show reliability when testing for internal reliability or test-retest reliability. Fresh vegetables, meat and poultry products, meat alternative products, fish and seafood products, leftovers, and shelf stable foods were shown to be reliable when testing Cronbach's alpha and ICC. However, dairy products, eggs and frozen foods were inconclusive when testing for reliability. The study suggests future testing with larger sample sizes should be conducted to demonstrate reliability of the food waste self-assessment tool.