Objective: To apply new psychometric criteria for DSM-IV Mild Neurocognitive Disorder (MND) to a sample of patients who have been treated for brain tumors. Design: Quasi-Experimental. Setting: Healthy adults were tested in the community and patients with brain tumors were tested as outpatients at the hospital or university. Participants: Psychometric criteria for MND were developed on a sample of 1,261 healthy adults between the ages of 18 and 79 from the Neuropsychological Assessment Battery (NAB) standardization sample. The clinical sample was 33 patients evaluated following their treatment for a primary or metastatic brain tumor. Interventions: Not applicable. Main Outcome Measures: An abbreviated version of the NAB, administered in approximately 2 hours, was used. This battery included 5 tests measuring attention and speed, 2 measuring language, 3 measuring learning and memory, two measuring spatial abilities, and 3 measuring executive functioning. All were also administered the Reynolds Intellectual Screening Test. Results: Criteria for possible and probable MND were derived by calculating the base rates of low scores in each domain for the healthy adults using several cutoffs. The criteria were stratified by level of intellectual ability. When applied to the patients treated for brain tumors, the classification breakdown was as follows: Probable MND=54.5%, Possible MND=36.4%, and Broadly Normal=9.1%. Conclusions: These new psychometric criteria for MND have low false positive rates in healthy adults and appeared to accurately identify impairment in patients treated for brain tumors.