Exclusive breastfeeding for the first 6 months of life is recommended as the optimal way to feed infants. This paper reviews the measurement of exclusive breastfeeding in Australian studies over the past 10 years. Only half the studies identified that claimed to measure exclusive breastfeeding used a definition consistent with the World Health Organisation. Three studies used 24-h or 7-day recall indicators that have been shown to produce overestimations of the prevalence of exclusive breastfeeding. Measurement of exclusive breastfeeding with a valid and consistent definition is vital for monitoring rates and trends, for comparison between different studies and countries and to reach conclusions on various health benefits. Any future measurement of exclusive breastfeeding in Australia should use the World Health Organisation definition and the 24 h recall study design should not be used for this purpose.