Infinitival-to omission errors (e.g., *I want hold Postman Pat) are produced by many English-speaking children early in development. This article aims to explain these omissions by investigating the emergence of infinitival-to, and its production/omission in obligatory contexts. A series of corpus analyses were conducted on the naturalistic data from one to 13 children between the ages of approximately 2;0 and 3;1 testing three hypotheses from two theoretical viewpoints. The data suggest that the errors are associated with different verb sequences (e.g., going-to and going-X) and their frequencies in the language to which children are exposed. The article concludes that these constructions compete for output when children are producing those verbs and that this supports the usage-based/constructivist account of the omission errors. Copyright © 2009 The Author(s).