Given the potentially harmful effects of parenting stress on parents, children, and their relationship, it is critical to have a reliable and valid measure of parenting stress in clinical and community samples. The Family Strain Index (FSI) is a brief questionnaire designed to measure stress and demand on parents of children with ADHD. The present study is the first to evaluate the psychometric properties of scores on the FSI in a general community sample. Parents (89% mothers) of 550 preschool children (aged 2-5 years; 50% boys) sampled through 17 kindergartens located in Danish cities and villages completed the FSI, the ADHD Rating Scale (RS)-IV Preschool Version, and a background questionnaire. FSI scores were characterized by restricted range and floor effects. The scale’s construct validity was not supported and the measurement repeatability after 1 month was low. The scale did have convergent validity as levels of parenting stress were associated with perceived ADHD behavior in off-spring, but overall, results did not encourage the use of the FSI as a measure of parenting stress in the general population. Measures that include more normative events may be more appropriate when attempting to capture parenting stress in general community samples.