The availability of a population of mostly known-age African elephants Loxodonta africana from Amboseli National Park, Kenya, provided a unique opportunity to assess the use of dung bolus diameter for estimating age. A predictive equation for estimating dung bolus diameters from elephants of known age was derived and was found to follow the typical growth pattern exhibited by changes in shoulder height and foot length. The relationship between measurements of dung bolus and age was particularly strong when growth rates were high (age 0–25 years). The dung bolus growth curve from Amboseli elephants was similar to that derived from another wild population of African elephants, suggesting that dung bolus diameter can be used to assess age structure in areas where it is impossible to construct independent prediction curves of age and dung bolus.