The aim is to evaluate the relationship between C-reactive protein (CRP) to albumin ratio (CAR) and radial artery thrombosis in patients undergoing radial angiography. We prospectively included 261 consecutive patients undergoing radial angiography, assessing radial artery diameter and thrombosis presence. The CRP values were significantly higher in radial artery thrombosis group compared with group without thrombosis (13.01 vs. 4.33 mg/l, p < 0.001, respectively). Also CAR was statistically significantly different between the group with thrombosis and the group without thrombosis (0.102 vs. 0.349, p < 0.001). Our study is the first to assess CAR in radial thrombus development post-procedure in patients undergoing radial angiography. CAR can be useful in determining radial artery thrombosis after the coronary angiography.