Meloxicam is a new non-steroidal anti-inflammatory drug (NSAID), with a favourable ratio of inhibition of cyclooxygenase-2 (COX-2)/cyclooxygenase-1 (COX-1), giving the drug the potential to produce few gastric adverse effects. The aim of this study was to investigate the efficacy and safety of meloxicam in patients with osteoarthritis (OA) of the knee. Five hundred and thirteen patients were treated in a double-blind trial comparing once-daily meloxicam 7.5 mg, 15mg, 30mg, or placebo (140, 134, 102 and 137 patients, respectively). Outcome measures included scores on Visual Analogue Scales (VAS) for pain on movement (primary endpoint) and pain at rest in the target joint as well as global efficacy. Lesquesne's index of severity and paracetamol consumption were also measured. Global tolerability and the occurrence of adverse events were monitored. Both meloxicam 7.5 mg and 15 mg were significantly more effective than placebo with respect to pain on movement (p < 0.01 and p < 0.03, respectively). Both doses of meloxicam compared favourably with placebo with respect to pain of the target joint at rest, although only the 15 mg dose achieved statistical significance (p < 0.02). Global efficacy showed a significant difference for both doses of meloxicam (p < 0.05 and p < 0.002 for 7.5 mg and 15 mg doses, respectively). Once daily meloxicam 7.5 and 15 mg is effective and well tolerated in the short term symptomatic treatment of OA of the knee.