BackgroundTo evaluate the second malignant tumors (SMTs) and non-tumor causes of death among patients diagnosed with localized and regional kidney cancer.MethodsPatients diagnosed with kidney cancer between 2000 and 2017 in the Surveillance, Epidemiology, and End Results (SEER) program database were identified. All causes of death for patients during the follow-up and standardized mortality ratio (SMR) were analyzed.Result113,734 patients with localized kidney cancer with 30,390 cases of death were analyzed. 60.4% of the death cases were due to non-tumor caused and 23.6% were second malignant tumors (SMTs). Main SMTs included cancers of lung and bronchus [n= 1,283, SMR: 1.00 (0.95–1.06)] and pancreas [n= 393, SMR: 1.27 (1.15–1.41)]. Causes of death for non-tumor mainly included heart diseases [n= 6,161, SMR: 1.25 (1.21–1.28)] and chronic obstructive pulmonary disease (COPD) [n= 1,185, SMR: 0.99 (0.94–1.05)]. 14,437 of 29,602 patients with regional kidney cancer died. 14.6% of all deaths were due to SMTs and 23.6% due to non-tumor causes. Main SMTs contained bladder cancer [n= 371, SMR: 10.90 (9.81–12.06)] and lung and bronchus cancer [n= 346, SMR: 1.21 (1.08–1.34)]. The main non-tumor death was heart disease [n= 1,424, SMR: 1.26 (1.2–1.33)]. When stratified by pathological types, patients with clear cell renal cell carcinoma (RCC) did not have increased mortality risks of bladder cancer and lung cancer but patients with non-clear cell RCC did.ConclusionSMTs and non-tumor diseases including lung and bronchus cancer, bladder cancer, pancreas cancer, diseases of heart, COPD, and cerebrovascular diseases are the leading causes of death besides kidney cancer and should be paid more attention during patients’ survival period.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40001-023-01176-6.