OBJECTIVES: One of the most disconcerting symptoms associated with Parkinson s disease (PD) and essential tremor (ET) is disabling tremor. Treatment options for this problem include low-risk pharmacologic therapy, with generally poor effectiveness and unfavorable side effects, or higher risk surgical interventions such as thalamotomy. We describe the health-related quality of life (HRQL) of patients with disabling tremor and assess their preferences for treatment outcomes in the form of utilities. METHODS: The MOS Short-Form 36 (SF-36) was used to characterize the patients HRQL. Standard gamble (SG) and visual analog scale (VAS) approaches were used to determine patient preferences among 12 PD and 9 ET health state descriptions. Data on patients appraisal of their current health state were also correlated with indicators of functional disability (Schwab & England) and HRQL (SF-36) using Spearman s Rho (?). RESULTS: Sixty-two patients, 31 tremor-dominant PD and 31 ET, participated in the study. Mean age of the sample was 65 years; 65% (n = 40) were male. PD and ET patients assigned the lowest mean SG health utilities to the health state description for a thalamotomy with partial or no improvement and permanent cognitive impairment (mean + standard deviation: PD: 0.56 + 0.25 and ET: 0.49 + 0.27). The highest mean utilities were assigned to thalamotomy with full improvement and no permanent impairment (PD: 0.95 + 0.02 and ET: 0.90 + 0.18). Current health state SG utilities were highly correlated with indicators of disability and HRQL (? = 0.35 to 0.64). CONCLUSIONS: Results suggest these patients are relatively risk averse. Subjects preferred disability associated with tremor over disability associated with cognitive or speech impairment that can occur with thalamotomy. The greatest patient-to-patient variability was found in the least desirable health states.