Celecoxib, a selective cyclooxygenase‑2 inhibitor, has chemo‑preventive activity against different cancer types, including bladder cancer (BC). However, the mechanisms by which celecoxib exerts its cancer preventative effects have yet to be completely understood. In the present study, the effect of celecoxib on the epithelial‑to‑mesenchymal transition (EMT) of BC cells and its potential molecular mechanisms were investigated. The results of the present study demonstrated that celecoxib inhibited the proliferation, migration, invasion and EMT of BC cells. Further investigation of the underlying mechanism revealed that celecoxib inhibited EMT by upregulating microRNA (miR)‑145 and downregulating the expression of transforming growth factor β receptor 2 and SMAD family member 3. Furthermore, the combination of celecoxib with miR‑145 mimics demonstrated an additive migration and invasion‑inhibitory effect in BC cell lines.