We used neutron activation analysis (NAA) to measure hand bone manganese (BnMn) in 19 adult males. Median BnMn was 0.89 μg/g dry bone (interquartile range = 1.07). After adjustment for age and occupation, higher ln(BnMn) was significantly associated with lower manual dexterity based on the Purdue Pegboard assembly task: β = −1.77, standard error = 0.79, p = 0.04. Due to the small sample size, these results should be interpreted cautiously. BnMn appears to be a promising biomarker, and should be further studied.