Prior sentencing research indicates that defendants with more extensive criminal histories receive more punitive dispositions and that criminal history influences sentencing decisions over and above its influence on the guideline recommended sentence. To date, these additional effects of criminal history have almost exclusively been treated as linear effects. However, there are plausible reasons to expect that criminal history could have curvilinear effects on sentencing outcomes that taper off at higher scores. The purpose of this paper is to explore the potential curvilinear effects of defendant criminal history on incarceration, sentence length, and downward departure decisions in federal criminal courts. The findings suggest that criminal history has curvilinear effects on each of these sentencing outcomes. As criminal history category increases, defendants receive more severe sentences, net of other factors, but only up to a certain threshold level, at which point criminal history effects taper off and even reverse.