Objective: To determine the incidence and extent of exacerbation of word-finding difficulty following anterotemporal lobectomy and to identify predictors of change. Design: Case-series study of qualitative and quantitative changes in confrontation naming ability before surgery and 1 year after surgery. Stepwise multiple regression analysis of predictors of postoperative naming change. Betting: A univeristy epilepsy surgery program. Participants: Fifty-nine consecutive patients. Intervention: Standard, en bloc anterotemporal lobectomy. Main Outcome Measure: Raw scores and types of errors on the 85-item Boston Naming Test. Results: A significant exacerbation of word-finding difficulty was noted that persisted at least 1 year after surgery in 25% of patients with left, speech-dominant anterotemporal lobectomy (Laterality X Time interaction [F=24.5; P<.0005]). ''Tip-of-the-tongue''-type errors were most frequent (F=54.66; P<.001), as opposed to paraphasic-type errors seen more frequently among patients with aphasia or dementia. Word-finding decline was worse among patients who underwent a left anterotemporal lobectomy and who were left-hemisphere speech dominant, older, or evaluated earlier in the postoperative course. Conclusions: Significant, persisting worsening of word-finding difficulties is not a rare consequence of a left anterotemporal lobectomy, as suggested by previous studies. Differences between these results and those of previous studies may reflect differences in extent of surgical resection and/or differential sensitivity of psychometric measures of naming to word-finding problems. Information regarding extent, frequency, and predictors of word-finding declines may be used in counseling surgical candidates about the potential cognitive side effects of anterotemporal lobectomy.