The aim of the study was to investigate the utility of the Tower of London-Drexel (TOL DX ) in assessing the executive deficits associated with Parkinsons disease (PD). We sought to determine whether the TOL DX would differentiate between (a) patients with PD and healthy control participants (HCP), (b) demented and nondemented patients, and (c) depressed and nondepressed patients. A new TOL DX score, stimulus bound, was introduced to assess utilization behaviors. Furthermore, the convergent and divergent validity of the TOL DX was examined. The TOL DX total move, rule and time violation, and stimulus-bound scores of patients with PD significantly differed from the HCP. Demented and nondemented patients also differed significantly in their TOL DX performance, with the stimulus-bound score being the most significantly differentiating score. However, the depressed and nondepressed patients did not differ in their TOL DX performance. Support was found for the convergent and divergent validity of the TOL DX. The clinical and theoretical implications of the findings are discussed.