Osteoarthritis (OA) is the most common form of arthritis, affecting 1 in 3 people over the age of 40 and women more so than men The goal of the study is to identify the relationship between body mass index (BMI), and C- reactive protein (CRP), with osteoarthritis (OA) in woman premenopausal subjects. In the study, 30 healthy woman without OA and 60 women patients with OA from general Balad Hospital in Salah Al-Den governorate were both included. Each subject was a premenopausal woman between the ages of 40 and 50. Clinical examination, X-ray diagnosis, and biochemical tests with ELISA and COBOS 6000 were used to determine the diagnosis of OA. This study proved that there is a significant increase in BMI (29.56+ 0.64) and CRP (0.703+ 0.09) mg/ml in premenopausal OA females than their level in the healthy control group (26.58) Kg/m2 and (0.379+0.11) mg/dl respectively. It’s noted that BMI has a negative correlation with CRP. Osteoarthritis in premenopausal women is strongly affected by BMI and CRP levels and it’s recommended to manage obesity and take CRP into consideration in routine OA tests.