To assess the efficacy of meloxicam, a non-steroidal anti-inflammatory drug (NSAID), on three human urinary bladder-cancer cell lines (HT1376, T24 and 5637) and on mice urinary bladder cancer chemically induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). The in vitro effects of meloxicam were assessed by optical microscopy, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method, flow cytometry and comet assay. In vivo, Hsd:ICR male mice were exposed to BBN in drinking water, over the course of 12 weeks. Subsequently, animals were treated with meloxicam by intraperitoneal route, for 6 consecutively weeks. Tumour development was evaluated by haematoxylin and eosin staining. Renal and hepatic functions, interleucin-6 (IL-6), C-reactive protein (CRP) and tumour necrosis factor (TNFα) were also evaluated. In vitro, meloxicam induced a significant (P<0.05) decrease of cell proliferation. A significant (P<0.05) cell cycle arrest on G0/G1 phase was also detected in all the cell lines, with a slight but significant increase of sub-G0/G1 fraction on T24 (P=0.006) and 5637 (P<0.001) cells. Also a significant (P<0.05) increase in DNA damage was found on meloxicam-treated cells. In vivo, the incidence of pre-neoplastic lesions induced by BBN was not affected by meloxicam treatment. However, although not statistically significant, the development of neoplastic lesions was inhibited by meloxicam treatment without significant alterations of renal or hepatic parameters. Meloxicam is effective on in vitro and in vivo models of urinary bladder cancer. These findings support that meloxicam deserves more attention on urinary bladder cancer study.