Objective: Data remain divergent regarding the activational effects of endogenous hormones on adult cognitive function. We examined the association between cognition, hormones and androgen receptor (AR) CAG repeat length in a large cohort of men. Design: Community-based, cross-sectional study of 3,369 men aged 40-79 years. Methods: Cognition tests were the Rey-Osterrieth Complex Figure, Camden Topographical-Recognition-Memory and Digit-Symbol Substitution. A fluid cognition (FC) z-score was computed from the individual tests. Testosterone (T), oestradiol (E2) and 5alpha-dihydrotestosterone (DHT) were measured by gas chromatography-mass spectrometry (GC-MS); dehydroepiandrosterone-sulphate (DHEAS), luteinising hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) by electrochemiluminescence. Free T/E2 were calculated from total hormone, SHBG and albumin. CAG repeat lengths were assayed by PCR genotyping. Results: Total and free T were associated with higher, LH and FSH with lower FC z-scores in age-adjusted linear regressions. After adjusting for health, lifestyle and centre, a modest association was only observed between DHEAS and a lower FC z-score (beta=-0.011, P=0.02), although this was driven by subjects with DHEAS levels >10micromol/L. Locally-weighted plots revealed no threshold effects between hormones and fluid cognition. There was no association between CAG repeat length and FC z-score after adjustment for age and centre (beta=-0.007, P=0.06), nor any interaction effect between CAG repeat length and hormones. Conclusion: Our results suggest endogenous hormones are not associated with a vision-based measure of fluid cognition among healthy, community-dwelling men. Further studies are warranted to determine whether 'high' DHEAS levels are associated with poorer performance on a broader range of neuropsychological tests.