In recent years, language scientists have studied bilingual language acquisition, often focusing on lexicon acquisition of Spanish-English speaking bilingual children. The recent increase in published literature is noteworthy; but compared to studies of English language acquisition, data for children who speak Spanish remain relatively rare. The current study examined the influence that exposure to a language has on Spanish and English vocabulary of young bilingual children. Of particular interest was the effect of language exposure on children's total vocabulary (TV) and translation equivalents (TEs). Sixteen Spanish-English speaking bilingual children, aged 20 to 37 months, served as participants. Data were collected using the Spanish and English short-form versions of the MacArthur Communication Development Inventory, as well as Spanish and English versions of a bilingual language survey and case-history questionnaire. Data analyses included descriptive comparisons of means, standard deviations, and ranges. In addition, correlation measures were used to examine the relation between language exposure and vocabulary. Results showed that Spanish exposure and English exposure were positively correlated with TV and TV with TEs. Further, bilingual children, as a group, exhibited a high number of TEs in their TVs. Overall, the results support the notion of interaction between exposure and lexical growth. In addition, lexical development for Spanish-English bilingual children appears to transfer between their two languages.