Incidental focus on form overtly draws learners' attention to linguistic items as they arise spontaneously--without prior planning--in meaning-focused interaction. This study examined the effectiveness of incidental focus on form in promoting second language (L2) learning. Seventeen hours of naturally occurring, meaning-focused L2 lessons were observed in 12 different classes of young adults in a private language school in Auckland, New Zealand. A total of 491 focus-on-form episodes (FFEs) were identified and used as a basis for individualized test items in which participants who participated in specific FFEs were asked to recall the linguistic information provided in them. The results revealed that learners were able to recall the targeted linguistic information correctly or partially correctly nearly 60% of the time 1 day after the FFE, and 50% of the time 2 weeks later. Furthermore, successful uptake in a FFE was found to be a significant predictor of correct test scores. These results suggest that incidental focus on form might be beneficial to learners, particularly if they incorporate the targeted linguistic items into their own production. [This research was supported by the Foundation for Science, Research, and Technology, New Zealand.]