Recurrence of bladder cancer following transurethral resection of bladder tumor (TURBt) is an obstacle in clinical management. In the current study, we investigated the antitumor activity of baicalein, a Chinese herbal medicine, against T24 bladder cancer cells in vitro. Baicalein inhibited growth and caused G1/S arrest of the cell cycle in the T24 cells. Moreover, baicalein induced apoptosis via loss of mitochondrial transmembrane potential (ΔΨm), release of cytochrome c and activation of caspase-9 and caspase-3. Baicalein inhibited Akt phosphorylation, downregulated Bcl-2 expression and upregulated Bax expression, which in turn increased the ratio of Bax/Bcl-2. Our results demonstrate that baicalein repressed growth inhibition and induced apoptosis via loss of ΔΨm and activation of caspase-9 and caspase-3 in T24 bladder cancer cells, which indicates that baicalein may be an effective agent in the clinical management of bladder cancer.