Tailgut cyst adenocarcinoma is a rare malignant tumor. We present 68Ga-FAPI PET/CT findings of tailgut cyst adenocarcinoma in a 46-year-old woman. Tailgut cyst adenocarcinoma on 68Ga-FAPI PET/CT showed increased tracer uptake. This case demonstrates the potential value of 68Ga-FAPI PET/CT for evaluating tailgut cyst adenocarcinoma.