The Use of Different Diagnostic Catheters-Radial-Trial sought to compare the safety and efficacy of one-catheter concepts (OCC) using Tiger II or BLK catheters with two-catheter concepts (TCC) using standard Judkins catheters for transradial coronary angiography. A total of 300 patients planed for coronary angiography were enrolled into this single-center, single-blinded trial. Patients were randomized in a 2:1 ratio to either OCC by Tiger II (n = 100) and BLK (n = 100) or TCC by Judkins (n = 100) catheters. Primary end point was time required to perform a complete coronary angiography. Coronary angiography duration was 603 ± 29 seconds and 552 ± 26 sec in the OCC and the TCC groups (p = 0.052). Fluoroscopy time was longer in the OCC (408 ± 28 sec) as compared with the TCC group (258 ± 28 sec, p = 0.009) and the amount of contrast volume used significantly higher (98 ± 5 ml vs 67 ± 4 ml, p < 0.001). Crossover rates were increased in the OCC as compared with the TCC group (37% vs 4%, p < 0.001). These effects were observed irrespective of OCC catheter type. In conclusion, this study demonstrates that OCC do not reduce angiography time, but are associated with an increased amount of contrast volume and longer fluoroscopy time as compared with TCC.