Background: Osteoarthritis (OA) is the main predominant type of arthritis and it is further established in the old ages. Person who suffers from OA naturally experiences joint stiffness and anxiety next time of rest or inactivity. Aims: Of the present study were evaluation of the levels of C-reactive protein, Calcium, and Vitamin D3 for some OA patients who attended Al-Refai Teaching Hospital. Methods: The current study was conducted at Al-Rifai Teaching Hospital from September 2023 to May 2024 .100 different samples were collected, males and females, from patients who visited the consultation at Al-Rifai General Hospital / Joints. Results were compared with the control group, which consisted of (100 different samples of males and females).  Results: The present result showed that the percentage of females suffering from OA was higher than the percentage of males, especially in the age group older than 36 years. The results of the current study showed no significant difference in Ca level in OA patients. The results of the current study also indicated a decrease in the level of vitamin D in the patient’s group was higher than in the healthy group. The results of the current study also indicated that 70% of patients had high level of C-reactive protein, on other hand the levels of vitamin D3in patients group were low in patients compared with control group Conclusions: According to our results we concluded that there was positive association between each of vitamin D and CRP with OA patients versus in control group but negative correlation between OA and Ca level.