Meloxicam is a non-steroidal anti-inflammatory drug (NSAID) that primarily has an antiproteinuric effect and is used for the treatment of chronic glomerular diseases. In chronic glomerular disease (CGD), proteinuria is involved in the production of tubulo-interstitial lesions and has an important role in their progression. CGD improves with steroid therapy and immunosuppression. In the case of a favorable outcome, a reduction in proteinuria is also attained. In some situations, this therapy is prohibited, requiring alternative medication. NSAIDs are one class of these alternative drugs; in addition to having anti-inflammatory actions, they also have antiproteinuric effects. The aim of the study has been to assess the effect of the anti-inflammatory treatment with meloxicam upon proteinuria as well as upon tubular lesions by determining urinary NAG in its dynamics. The study was performed on 12 patients with CGD, 6 of them with nephrotic syndrome. On all patients we administered treatment with meloxicam 15 mg/day, 30 days. On all patients we performed proteinuria and urinary N-acetyl b D glucosaminidase (NAG) at the beginning, after 7 days and after 30 days of treatment. A 24-hour urine collection was taken from all patients. The urinary protein concentration was determined with the use of the Dimension (Dade Behring, Inc., Newark, DE, USA) clinical chemistry system UCFP method. We found a decrease of proteinuria under treatment from 2.85 +/- 1.69 g/24h to 1.53 +/- 0.83 g/24h, which was significantly lower, compared to the initial measurement (p = 0.01878). After 30 days of treatment with meloxicam, urinary NAG decreased from 10.6 +/- 12.56 U/g creatinine to 6.44 +/- 7 U/g, a decrease that was statistically non-significant. We observed a strong correlation between initial urinary NAG and initial proteinuria ri = 0.924, p < 0.001 and between final urinary NAG and final proteinuria rf = 0.856, p < 0.001. Our study revealed the favorable effect of meloxicam on patients with CGD on a 30-day treatment phase reflected on the evolution of proteinuria. Only in one case we did reveal a possible deleterious effect of this treatment. The assessment of the effect on tubulo-interstitial lesions in this short treatment period through urinary NAG assessment indicated only a modest and statistically non-significant response. We consider that meloxicam can be a useful drug in the treatment of proteinuric glomerular diseases.