Two rhesus monkeys were trained to learn eight 4-item lists, each composed of 4 different photographs. Lists were trained in successive phases: A, A—»B, A—»B—»C, and A—»B-^»C—>D. After List 4, retention, as measured by the method of savings, was, on average, 66% (range: 44- 84%). Indeed, all 4 lists could be recalled reliably during a single session with neither a decrement in accuracy nor an increase in the latency of responding to each item. Response latencies on a subset test employing all possible 2- and 3-item subsets of each 4-item list support the hypothesis that monkeys form linear representations of a list. Latencies to Item 1 of a subset varied directly with the position of that item in the original list. On List 1, latencies to Item 2 varied directly with the number of intervening items between Item 1 and Item 2 in the original list. During the acquisition of Lists 5-8, both Ss mastered the A—»B and A—»B—»C phases of training in the minimum number of trials possible. Recent studies of serial learning by monkeys and pigeons have provided ample evidence that these nonverbal organisms can learn to produce arbitrary lists composed of arbitrary