INTRODUCTION: Our aim is to evaluate whether previous non-urothelial malignant history affects the clinical outcomes of patients with non-muscle invasive bladder cancer (NMIBC). PATIENTS AND METHODS: We identified 1097 cases treated by transurethral resection of bladder tumors for initially diagnosed NMIBC at our four institutions between 1999 and 2017. We compared clinical characteristics and outcomes between NMIBC patients with and without previous non-urothelial malignant history and investigated whether smoking status and treatment modality for previous cancer affected NMIBC outcomes. RESULTS: A total of 177 patients (16.1%) had previous non-urothelial malignant history (malignant history group). The 5-year recurrence-free survival rate and the 5-year progression-free survival rate in the malignant history group was 46.4% and 88.3%, respectively, which was significantly lower than that in the counterpart (60.2% p = 0.004, and 94.5% p = 0.002, respectively). A multivariate Cox regression analysis identified previous non-urothelial malignant history as an independent risk factor for tumor recurrence (p = 0.001) and stage progression (p = 0.003). In a subgroup of patients who were current smokers (N = 347), previous non-urothelial malignant history was associated with tumor recurrence and stage progression. In contrast, previous non-urothelial malignant history was not associated with tumor recurrence or stage progression in ex-smokers or non-smokers. In a subgroup analysis of NMIBC patients with previous prostate cancer history, those treated with androgen deprivation therapy had a significantly lower bladder tumor recurrence rate than their counterparts (p = 0.027). CONCLUSIONS: Previous history of non-urothelial malignancy may lead to worse clinical outcome in patients with NMIBC, particularly current smokers.