Trail Making Test (TMT) performance was investigated in 765 elderly volunteers (age range 60 to 96 years), 58 of whom met DSM-III-R criteria for dementia and 40 dementia 'suspects,' who showed mild changes in one or two cognitive domains. Cross-sectional analyses of the 667 nondemented participants, revealed significant age effects in completion times for both Parts A and B. Prevalence of errors increased with age on Part B, but not on Part A. Two-year longitudinal changes were examined in a subset of the nondemented sample (n = 385). Significant slowing was found for Part B, but not for Part A, with older age groups showing the greatest change. Error rates did not increase. Dementia status accounted for a significant proportion of the variance in completion times after accounting for age, education, and gender. Receiver operating characteristic analyses suggest that the TMT may be useful in screening for cognitive dysfunction.