Endometrial carcinoma (EC) is a common gynecological malignancy. Vaginal cuff brachytherapy (VBT) is an adjuvant treatment for EC. Since a single-channel cylinder sometimes delivers inadequate dose coverage to the vaginal apex, three-dimensional (3D) printing technology can be used to achieve satisfactory dose distribution. Here, we report the first case of an EC patient with Herlyn-Werner-Wunderlich syndrome (HWWS) treated with VBT using 3D-printed applicators. Case Presentation: Here, we present a case study of an endometrial cancer patient with HWWS who underwent surgery. During adjuvant radiotherapy, 3D-printed applicators were used in VBT. To accomplish the reconstruction of the source pathways on magnetic resonance imaging, catheters with copper sulfate were placed in two 3D-printed applicators. The early tolerance of this treatment was positive. During the 6-month follow-up, locoregional recurrence was not detected. Conclusion: Our findings strongly indicate that VBT with 3D-printed applicators may be a reasonable treatment option for EC with HWWS.