Judicial sentencing decisions should be guided by facts, not by chance. The present research however demonstrates that the sentencing decisions of experienced legal professionals are influenced by irrelevant sentencing demands even if they are blatantly determined at random. Participating legal experts anchored their sentencing decisions on a given sentencing demand and assimilated toward it even if this demand came from an irrelevant source (Study 1), they were informed that this demand was randomly determined (Study 2), or they randomly determined this demand themselves by throwing dice (Study 3). Expertise and experience did not reduce this effect. This sentencing bias appears to be produced by a selective increase in the accessibility of arguments that are consistent with the random sentencing demand: The accessibility of incriminating arguments was higher if participants were confronted with a high rather than a low anchor (Study 4). Practical and theoretical implications of this research are discussed.