Purpose: We aimed to evaluate the entrance skin dose (ESD) during radiofrequency catheter ablation (RFCA). Methods: The X-ray fluoroscopic mode (70 kV, 7.5 p/s, 13.0 × 13.0 cm) was evaluated at C-arm angles of 45° left anterior oblique and 35° right anterior oblique. The bed height was raised by 4 to 8 cm from the bed base-point position (BP, 0 cm). Fluoroglass dosimeters were placed in three lines at 5-cm intervals on the surface of the phantom. The maximum skin dose conversion factors were calculated as the ratio of the calculated and the actual maximum skin doses. Results: At heights of 6 and 8 cm, calculated ESDs had peak values of 93.0 ± 0.2 and 74.5 ± 2.7 mGy, respectively, whereas the actual maximum skin doses were in the range of 47.4 ± 0.2 to 59.5 ± 0.2 mGy. The maximum skin dose conversion factors were 0.79, 0.87, 0.53, 0.64, and 0.72 at bed heights of 0, 2, 4, 6, and 8 cm from the BP, respectively. Conclusion: A maximum skin dose conversion factor should be taken into consideration when determining the maximum skin dose in overlapping irradiation fields.