Healthy monolingual older adults experience changes in their lexical abilities. Bilingual individuals immersed in an environment in which their second language is dominant experience lexical changes, or attrition, in their first language. Changes in lexical skills in the first language of older individuals who are bilinguals, therefore, can be attributed to the typical processes accompanying older age, the typical processes accompanying first-language attrition in bilingual contexts, or both. The challenge, then, in understanding how lexical skills change in bilingual older individuals, lies in dissociating these processes. This paper addresses the difficulty of teasing apart the effects of ageing and attrition in older bilinguals and proposes some solutions. It presents preliminary results from a study of lexical processing in bilingual younger and older individuals. Processing differences were found for the older bilingual participants in their first language (L1), but not in their second language (L2). It is concluded that the lexical behaviour found for older bilinguals in this study can be attributed to L1 attrition and not to processes of ageing. These findings are discussed in the context of previous reports concerning changes in lexical skills associated with typical ageing and those associated with bilingual L1 attrition. (Contains 2 tables, 3 figures, and 7 notes.)