For over 20 years, SLA research has been investigating the role of negotiation in second language acquisition. While much attention has been given to an examination of the conditions that are necessary for acquisition and the factors that can facilitate opportunities for negotiation, limited attention has been given to a longitudinal study of the relationship between negotiation and language learning. This paper reports on a study which investigated the extent to which successfully negotiated linguistic features were retained over a period of 12 weeks. The 30 pre-intermediate ESL learners who participated in the study were asked to repeat two different communication tasks (information gap and decision-making) 1 week and 12 weeks after their first performance. Vocabulary items, particularly concrete nouns in the information gap task, were negotiated more often than pronunciation and grammar items. Noticing the gap between their problematic utterances and the feedback they received from their conversational partners, the participants immediately modified close to two-thirds of these utterances, indicating that learning may have occurred. There was a high retention rate both one week and 12 weeks later for these negotiated items.