Recent studies showed that women were older than men when achieving their fastest marathon race time. These studies, however, investigated a limited sample of athletes. We investigated the age of peak marathon performance in a large sample of female and male marathon finishers by using data from all finishers. We analyzed the age of peak marathon performance in 1-year and 5-year age intervals of 451,637 runners (i.e. 168,702 women and 282,935 men) who finished the ‘New York City Marathon’ between 2006 and 2016, using analysis of variance and non-linear regression analysis. During these 11 years, men were faster and older than women, the participation of women increased disproportionately to that of men resulting in a decrease of the male-to-female ratio, and relatively more women participated in the younger age groups. Most women were in the age group 30-34 years
and most men in the age group 40-44 years. The fastest race time was shown at 29.7 years in women and 34.8 years in men in the 1-year age intervals, and in age group 30-34 years in women and 35-39 years in men in the 5-year age intervals. In contrast to existing findings reporting a higher age of peak marathon performance in women compared to men, we found that women achieved their best marathon race time ~5 years earlier in life than men in both 1-year and 5-year age intervals. Female athletes and their coaches should plan to achieve their fastest marathon race time at the age of ~30 years.