Interference susceptibility has been suggested to be a major factor for episodic memory impairment in healthy older adults. Previous work has shown that retrieval practice can reduce proactive interference and thus enhance learning and memory in younger adults, a finding referred to as the forward effect of testing in the literature. This study examined the late developmental trajectory of the forward effect in middle-aged and older adults (40 to 79 years of age). Participants studied three lists of items in anticipation of a final cumulative recall test. In the testing condition, participants were tested immediately on Lists 1 and 2 after initial study, whereas in the restudy condition, they restudied Lists 1 and 2. In both conditions, participants were tested immediately on List 3. The results of the immediate List-3 recall test showed a reliable forward effect of testing, with interim testing of Lists 1 and 2 enhancing List-3 recall and reducing the number of prior-list intrusions. Notably, this effect of testing was found independent of participants’ age. These results suggest that retrieval practice can reduce proactive interference in middle-aged and older adults. Together with recent findings on the presence of the backward effect of testing in older adults–that is, improved recall of studied material after retrieval versus restudy, these findings indicate that retrieval practice can be a very powerful tool to delimit memory impairment in older age. (PsycINFO Database Record (c) 2019 APA, all rights reserved)