A chronically elevated white blood cell (WBC) count is a risk factor for morbidity and mortality. The present research tests whether facets of impulsivity – impulsiveness, excitement-seeking, self-discipline, and deliberation – are associated with chronically elevated WBC counts. Community-dwelling participants (N=5,652) from Sardinia, Italy, completed a standard personality questionnaire and provided blood samples concurrently and again three years later. Higher scores on impulsivity, in particular impulsiveness and excitement-seeking, were related to higher total WBC counts and higher lymphocyte counts at both time points. Impulsiveness was a predictor of chronic inflammation: For every standard deviation difference in this trait, there was an almost 25% higher risk of elevated WBC counts at both time points (OR=1.23, 95% CI=1.10–1.38). These associations were mediated, in part, by smoking and body mass index. The findings demonstrate that links between psychological processes and immunity are not limited to acute stressors; stable personality dispositions are associated with a chronic inflammatory state.