Abstract The Continuous Performance Test (CPT) is a widely used measure of sustained attention, which is a preferred tool for assessing various mental functions. A well-established norm for CPT is essential when choosing a suitable threshold for classifying individuals as either case (CPT impairment) or non-case. The CPT performance of 900 adults who were randomly chosen from a community survey was measured to establish the norms for subgroups with different gender, age, and educational levels. The results revealed that age and educational level are significantly associated with the performance sensitivity (d′) of CPT. Male subjects perform better than female subjects. Seventeen percent of the subjects scored higher on the masked CPT than on the unmasked CPT. Subjects who could not finish the masked CPT had the characteristics of older age and fewer years of education. When classifying a patient as case or non-case, his/her CPT performance should be considered relative to the norms for his/her gender, age, and educational levels.