Osteoarthritis (OA) is the most common type of arthritis. It is characterized by the loss of cartilage and pain ultimately leading to difficulty in movement. Glycoprotein osteopontin (OPN) is an essential regulator that plays a critical role in developing osteoarthritis. The study aims to determine the level of OPN in the serum of patients with OA and its correlation with the content of calcium (Ca), phosphorus (P), and magnesium (Mg). The study was conducted on 92 male and female patients aged between 30 and 65, categorized into mild, moderate, and severe groups through clinical examination and X-rays. The control group consist of 58 healthy males and females 30-65-year old. OPN was measured using the ELISA technique, and minerals were estimated using spectrophotometry. It was shown that in OA patients, OPN level increased highly significant when compared with the control group (10.7 ± 3.4 ng/ml) and depended on OA severity. In patients with severe OA, it was higher (47.5 ± 8.1 ng/ml) than in groups with moderate (14.8 ± 4.5 ng/ml) and mild (12.1 ± 3.1 ng/ml) extent of the disease. We showed a significant positive relationship between OPN and phosphorus levels and a negative significant correlation between OPN and calcium, calcium/phosphorus ratio, and magnesium. These findings underscore the potential of OPN as a valuable biomarker for diagnosing the severity of osteoarthritis and monitoring the effectiveness of treatment. Keywords: calcium, magnesium, osteoarthritis, osteopontin, phosphorus.