Purpose. The aim of this case study is to define the involution of simple and complex reaction times in groups of adult men and women. Basic procedure. The tests were carried out during the years 2007-2008 among 128 men and 136 women aged between 21 and 80. Those examined were divided into three groups according to their calendar age. In order to define the meaning of differences of the analyzed reaction time between the results of the three age groups, the analysis of variance (ANOVA) method for independent attempts was used. Additionally, normalized differences between the groups as well as indices of sexual dimorphism were defined. Main findings. Among both men and women, gradual deterioration of reaction time performance with age can be observed. The scale of normalized differences shows that the most distinct differences are noticed between the first and the third group. They amount up to 1.3 of the standard deviation in men and up to 1.7 in women. Conclusions. The results derived from the following study confirm a long period of relative stabilization for all simple and complex reaction times among both genders. Significant involution of reaction times can be observed for all analyzed features only after the age of 55. Indices of sexual dimorphism indicate that men gain better results in all age groups. Indices of sexual dimorphism diminish with age.