Twenty-three patients with mild dementia of the Alzheimer's type (DAT) or frontotemporal type (DFT) and age- and education-matched control subjects were administered tests of complex fluency involving divergent thinking and tests of letter, category, and figural fluency. The tests of complex fluency discriminated the dementia patients from control subjects more strongly than did the other fluency tests. The results suggest that divergent thinking as assessed by complex fluency tests is a cognitive domain that is impaired early in the course of dementia. The sensitivity of complex fluency tests compared to that of letter, category, and figural fluency tests may be related to greater demands for conceptualization in relating stimulus attributes to function and greater demands for flexible thinking during self-directed search processes.