The quality of the judicial system depends upon the quality of decisions that judges make. Even the most talented and dedicated judges surely make occasional mistakes, but the public understandably expects judges to avoid systematic errors. This expectation, however, might be unrealistic. Psychologists who study human judgment and choice have learned that people frequently fall prey to cognitive illusions that produce systematic errors in judgment. Even though judges are experienced, well-trained, and highly motivated decision makers, they might be vulnerable to cognitive illusions. We report the results of an empirical study designed to determine whether five common cognitive illusions (anchoring, framing, hindsight bias, inverse fallacy, and egocentric biases) would influence the decision-making processes of a sample of 167 federal magistrate judges. Although the judges in our study appeared somewhat less susceptible to two of these illusions (framing effects and the inverse fallacy) than lay decision makers, we found that each of the five illusions we tested had a significant impact on judicial decision making. Judges, it seems, are human. Like the rest of us, their judgment is affected by cognitive illusions that can produce systematic errors in judgment.