Abstract: The authors reported a case of clear cell renal cell carcinoma (ccRCC) complicated with renal abscess on ¹⁸F-fluorodeoxyglucose (FDG) PET/CT imaging. The combination of ccRCC and renal abscess is very rare in clinical practice. ¹⁸F-FDG PET/CT imaging showed mild increased ¹⁸F-FDG uptake in the ccRCC area, while the ¹⁸F-FDG uptake in the renal abscess area was higher than that in the overall ccRCC uptake. Meanwhile, enhanced CT of ccRCC showed a "fast in and fast out" enhancement pattern, while the renal abscess area within it showed delayed enhancement, which can detect the infected area in the ccRCC and provide a basis for clinical diagnosis and treatment.