Accurate prognosis is a key factor in establishing optimal therapeutic decisions; yet in the case of bladder cancer (BlCa) current prognostic indicators cannot ensure optimal disease management. Here, we aimed to evaluate the previously unexplored clinical potential of the urological cancer-related miR-145, miR-143 and miR-224 in BlCa. A total of 279 bladder tissue specimens were included in this study (133 BlCa, 107 adjacent normal and 39 healthy samples). Total RNA was extracted from tissues, it was polyadenylated and reverse transcribed to cDNA. The expression of target molecules was measured via quantitative real-time PCR. The expression levels of both miR-143 and miR-145 were significantly decreased, whereas those of miR-224 were increased in BlCa. Receiver operating characteristic curve analysis indicated a significant discriminatory capacity for miR-143/miR-145 levels. Important associations with disease aggressiveness were observed for all three microRNAs; elevated levels were observed in tumors of higher stage and grade, as well as in ‘high-risk’ TaT1 patients. More importantly, high miR-143/145 levels could effectively prognose inferior overall survival for muscle-invasive patients and could independently predict the progression of superficial tumors. Finally, the combination of miR-143/145 overexpression with the widely used prognostic markers of European Organization for Research and Treatment of Cancer-risk groups or recurrence at the first follow-up cystoscopy resulted to a superior positive prediction of non-muscle-invasive bladder cancer short-term progression compared with the use of the abovementioned markers alone. The cancer-related miR-143, miR-145 and miR-224 were investigated for the first time in the clinical setting of BlCa, and miR-143/145 cluster constitutes a novel marker helpful for providing an enhanced prediction of oncologic outcome for BlCa patients.