Evidence for human learning without awareness of what is learned has been sought in serial reaction time (SRT) tasks (Willingham, Nissen & Bullemer, 1989), yet a number of criticisms have been levelled at such tasks (e.g. Shanks & St. John, 1994). Here we provide a novel, two-choice SRT paradigm whereby the locations of response stimuli are sometimes predicted by a color-filled square that appears before each stimulus. Two out of eight colors are predictive on 80% of trials, and performance on these consistent trials was faster than on the other six colors that were equally likely to result in either of the two possible responses. A prediction task and interview followed the task, on which participants performed at near (slightly below) chance levels. We suggest that this task is a useful tool for studying associative learning in humans, as it provides reliable effects that appear to demonstrate implicit learning.