Abdominal profile index (API) is often used as an index of body condition in studies of anatids. However, few studies have statistically tested the relationship between API and body condition. In this study, we investigated the relationship between API and body condition of Greater White-fronted Geese Anser albifrons, taking into account the structural size effect on body condition. It was found that body mass, excluding the structural size effect, has a positive relationship with API. As API explained only 26% of the variance in body condition, we discuss the limitations of the method and the situations in which it can be used effectively.