This paper investigates object omission in French longitudinal production from two English-speaking children (Lightbown, 1977). Similar patterns of object omission are observed: direct objects start being dropped as transitive verbs are emerging and licit and illicit null objects occur in all recordings thereafter. Moreover, the incidence of illicit null objects drops at about the same time in both children (month 20), which corresponds to the moment object clitics start being used productively and to the end of the root infinitive period (Prevost, 1997). I argue that object omission is an instance of clitic-drop and is related to processing difficulties. In particular, both the projection of full-fledged representations and the production of object clitics (which occupy non-canonical object positions in French) increase computational complexity for children. Object-drop in child L2 French does not seem to be affected by L1 transfer nor to be related to significant difficulties with properties at the syntax/pragmatics interface. [This research was supported by FQRSC.]