Abstract : Lower 2D:4D, a proxy indicator of in-utero testosterone exposure, is more common among men. Previous studies reported its association with aggression, risk-taking behavior as well as the risk of developing osteoarthritis. The current study aimed to determine the association between the 2D:4D and the presence of primary tibiofemoral osteoarthritis among women. The study was conducted as a case-control. The 2D:4D in a group of women with primary tibiofemoral osteoarthritis was compared with a group of controls (without osteoarthritis). Measurement of the finger length was taken from the tip of the respective fingers to the basal crease. The length of the index finger (2D) was divided by the length of the ring finger (4D) to obtain the 2D:4D. The ratio was classified into three types. Type I (2D>4D, common female pattern), type II (2D=4D, intermediate pattern), and type III (2D<4D, common male pattern). A total of 476 women with tibiofemoral osteoarthritis (OA group) and 474 controls were randomly selected for the study. In the OA group, 48% (n=231) were type III, followed by type I (28%) and type II (24%). The commonest among the controls was the type I (n=218, 46%). The difference between 2D:4D in the OA group and the controls was statistically significant (p<0.001). Type III 2D:4D in women can predict the potential risk of tibiofemoral osteoarthritis. We suggest women with type III 2D:4D should be indicated for clinical assessment and risk stratification of tibiofemoral osteoarthritis.