To clarify the influence of eustachian tube (ET) anatomical measurements on the success rate of Type 1 cartilage tympanoplasty. Material and Methods: The medical records of 99 patients, who underwent cartilage Type 1 tympanoplasty were reviewed retrospectively. The length of ET (ETl), tubotympanic angle (TTa), ET-Reid horizontal plane angle (ETa), and ET pretympanic diameter (ETd) were measured on temporal bone computed tomography using the multiplanar reconstruction technique. Two groups were created based on the anatomical success of the procedure. Group 1 consisted of ears with successful anatomic outcomes and Group 2 consisted of ears without successful anatomic outcomes a year postoperatively. The ET anatomical measurements of Groups 1 and 2 were compared. Results: A total of 108 ears (90 unilateral and 9 bilateral ears of 99 patients) were included in our study. The differences between the ETl, TTa, ETa, and ETd of Groups 1 and 2 were statistically insignificant. Conclusion: Our study showed that ETl, TTa, ETa, and ETd do not have a significant role in the anatomic outcome of Type 1 cartilage tympanoplasty. Using cartilage grafts in Type 1 tympanoplasty might be preferred to rule out the anatomical disadvantages regarding the ET. Studies with greater sample sizes are required to assess both the anatomy and function of the ET in the success rate of Type 1 tympanoplasty with various graft types.