Although small cell neuroendocrine carcinoma of the ureter (ureteral SCNEC) is rare, it always leads to a poor prognosis. Also, no treatment recommendation has been given for ureteral SCNEC, with only PD-1/PD-L1 inhibitors being used for its treatment. Here, we report a case of atypical symptoms of cardiac infarction caused by a PD-1 inhibitor used in the treatment of ureteral SCNEC and hope to address concerns regarding the possible cardiac toxicity caused by PD-1/PD-L1 inhibitors in ureteral SCNEC patients.