The ratio between length of the 2nd (the „„index‟‟ finger) and 4th (the „„ring‟‟ finger) digit (2D:4D) is positively correlated with prenatal exposure to estrogen, negatively correlated to prenatal exposure to testosterone and traits beneficial sport performance. The purpose of this study was to explore the relationships between digital finger ratio (2d:4d) and mental toughness with sporting achievement. Participants includes 268 (male = 157 and females =111) sports people of 18-25 years from different universities of Haryana, India, Vernier Caliper was used to measure digit ratio of both hands and mental was assessed with Alternative Psychological Performance Inventory (PPI-A, Golby et al., 2007) and Sport Mental Toughness Questionnaire (SMTQ, Sheard et al., 2009). A significant difference (p= 0.01) for 2d:4d was found between the high and low sports achievement groups. Group with low 2d:4d differ significantly (p=0.001) on all sub scale of mental toughness and sports mental toughness then high 2d:4d group. Specifically, this difference was significant when comparing the highest (National /AIU) and lowest (state/university) groups. Perhaps there is a threshold for prenatal testosterone‟s influence upon sporting ability. It is proposed that high prenatal levels of testosterone may contribute to the development of increased mental toughness required for sporting success.