This paper provides an analysis of copula be in the developing English grammar of two English/Spanish simultaneous bilingual children, drawing from Becker's (2002, 2004) study of copula omission in L1 English monolingual child data, in order to contribute to the debate on whether omission in child language is to be accounted for syntactically (Hyams and Wexler 1993) or as the result of a processing deficit (Valian 1991, Valian and Eisenberg 1996). The analysis shows that a grammatical account is favored over a processing one (as in Becker's study) and that, even though there are some similarities in the overall omission patterns with respect to the Locative/Nominal predicate dichotomy, the omission rates in these English bilinguals' data are significantly lower than the omission rates displayed by Becker's monolinguals. This difference is proposed to be attributed to the lexical transparency of Spanish copula estar and the availability of the contrast with ser, which seems to play a role in the need to incorporate the inflectional level and, therefore, the use of the overt copula.