In healthy young adults motor learning is typically improved by practice under conditions of high contextual interference such as that created when a series of skills are practiced in a random sequence. The authors examined whether individuals with Parkinson's disease and age-matched older adults might also benefit from such a learning environment. Participants learned 3 peg placement movements under both random practice and blocked practice schedules. Participants completed free-recall, cued-recall, and transfer tests 1 day and 1 week following practice. During acquisition all learners had shorter movement times (MTs) during blocked than random practice but during retention testing, MTs were shorter if the patterns had been learned with random practice. Fewer errors during free recall following random practice were evident in both groups of learners and MTs to complete a novel transfer task were shorter following random practice. These findings suggest employing a cognitively challenging practice environment might improve motor skill learning in elderly learners and in people with Parkinson's disease.