Context:Bladder neoplasms are a well-studied subject in medicine. However, the evidence of bladder neoplasms in children and the young adult population (≤40 years), particularly in Saudi Arabia, is lacking.Aims:The aims of this study were to identify histopathological characteristics as well as clinical features, prognosis, and treatment of bladder neoplasms in this age group in a single tertiary referral center, Riyadh, Saudi Arabia.Settings and Design:A retrospective cohort study.Materials and Methods:Children and young adults (≤40 years) diagnosed with epithelial and mesenchymal bladder neoplasms from 1994 to 2017.Statistical Analysis Used:Descriptive data are presented as mean (standard deviation) or median (interquartile range) for continuous variables and n (%) for categorical variables. Statistical Package for Social Sciences version 23 was used.Results:Thirty-eight cases were identified. The majority, 71.1% (n = 27) were male. The median age of diagnosis was 33 years ranging from 1 to 40 years. Nearly 45% (n = 17) were smokers. Macroscopic hematuria was present in 57.8% (n = 22). The most common histopathology was papillary urothelial carcinoma (n = 18, 58%). All mesenchymal neoplasms accounted for 18.4% (n = 7). Of all malignancies, 63.2% (n = 24) and 44.7% (n = 17) were low stage and low grade, respectively. Transurethral resection of bladder tumor (TURBT) was conducted for 81.6% (n = 31). The mean length of follow-up was 36.05 months (±39.4 months). Recurrence occurred in 15.8% (n = 6) and 7.9% (n = 3) had progression. Distant metastasis was reported in 5.3% (n = 2). Nearly 8% (n = 3) died during their follow-up.Conclusions:Bladder malignancies at the early fourth decade of life tend to be a low stage and low grade. The most common histopathology was papillary urothelial carcinoma. Management should be based on the clinical and histopathological features. However, most of the patient underwent TURBT.