During early stages of second language acquisition adult learners make frequent errors of lexical form. An experiment was performed to examine this effect in the laboratory. More and less fluent bilinguals in English and Spanish performed a translation recognition task in which they decided whether the second of two words was the correct translation of the first. In the critical conditions of the experiment the words were not correct translation equivalents, but related by lexical form (e.g., man-hambre (hunger) instead of man-hombre (man)) or by meaning (e.g., man-mujer (woman) instead of man-hombre (man)). Less fluent participants suffered more interference for form-related than for semantically related words relative to unrelated controls, but the reverse pattern held for more fluent participants. The results support a progression from reliance on word form to reliance on meaning with increasing proficiency in the second language. The performance of the more fluent bilinguals further suggests that the ability to retrieve semantic information directly for second-language words can potentially override some of the costs associated with lexical competition in languages that access shared lexical features.