Objectives. The aim of this study was to determine the radial artery diameter of patients through angiography and evaluate the feasibility of using wider sheaths for radial interventions. In addition, any parameters that could affect the radial artery diameter were also evaluated. Background. The radial artery is a suitable, beneficial route for coronary procedures and is considered a good alternative to transfemoral access. However, a small radial artery diameter may make complicated coronary and peripheral procedures even more difficult. Therefore, an evaluation of the radial artery diameter may help the interventional cardiologist to select the instruments and techniques that are the most appropriate for the patient. Methods. Radial artery diameters were calculated in 93 consecutive patients who underwent a transradial coronary procedure along with simultaneous radial angiography, and the anthropometric parameters that might affect the diameter and the association between vessel diameter and pain experienced by the patient during sheath removal were investigated. Results. A total of 97 patients (69 males [71.1%]; 28 females [28.9%]) between 30-89 years of age (mean age, 59.0 +/- 10.6 years) were included in the study. Four patients were excluded due to the failure of the radial procedure. The radial artery diameters were measured angiographically in the remaining 93 patients, and the procedural success rate was 95.8%. The mean radial artery diameters were 2.3 +/- 0.38 mm in males, 2.1 +/- 0.42 mm in females, and 2.3 +/- 0.40 mm for the entire study population. Body weight and distal and proximal wrist diameters showed positive and significant correlations with the radial artery diameter (P=.025, P=.013, and P=.032, respectively). Conclusion. In this cross-sectional study, since the mean radial artery diameter was 2.3 +/- 0.40 mm, the coronary procedures performed via the radial route can be deemed successful. Moreover, we found no independent predictors of radial artery diameter. Among the patients, 74% had coronary artery diameters of 6 Fr or larger. As long as the ulnar collateral circulation is sufficient, the transradial procedure can be safely performed without considering any other anthropometric parameters.