Although it is very useful in daily life, children have difficulties to estimate durations using conventional time units. The aim of the present study was to examine whether young children aged three, five and eight years and adults are able to categorize familiar actions according to their duration, by using a new task not relying on knowledge of conventional time units. Participants performed a forced-choice categorization task in which short, medium or long target action durations had to be paired with one of three comparison action durations (short, medium or long). Results showed that as age increased so, too, did the percentage of accurate temporal categorizations, while that of temporal categorization errors decreased. Moreover, except at three years, the least frequent error consisted in categorizing a short action as a long one. These results are discussed in the light of event representation theory and the role of experience in temporal cognition.