OBJECTIVES: High costs of rheumatoid arthritis (RA) and osteoarthritis (OA) due not only to high morbidity, disability and mortality levels, but also basis medications and treatment of adverse events which are very expensive. METHODS: We analyzed the efficacy and safety data from randomized clinical trials and systematic reviews of symptomatic treatment OA and RA patients with meloxicam and diclofenac. We were searching data on the: www.cochrane.org, www.pubmed.gov, www.clinicaltrials.gov. A model “decision tree” was built based on two information sources: 1) literature review; 2) cost databases. We calculate the average direct costs of one serious cardiovascular thromboembolic adverse event and one serious gastrointestinal adverse event in Ukraine. We determined the CER based on costs from our “decision tree” model and data from the IMPROVE study RESULTS: Direct costs of one serious cardiovascular and gastrointestinal adverse event were USD$590.29 and USD$613.81 (1 USD$ = 7.95 UAH on 10.01.2011), respectively. Direct costs of 60 days symptomatic treatment of 100 RA or OA patients with meloxicam 7.5 mg daily and diclofenac 100 mg daily were USD$2057.99 and USD$4975.22, respectively. CER meloxicam was calculated 30.72 and CER diclofenac - 117.34. The one-way sensitivity analysis performed with the most relevant varables confirmed this tendency. CONCLUSIONS: Results show that Meloxicam 7.5 daily is more economical effective versus diclofenac 100 mg daily for symptomatic treatment of RA and OA patients taking into account probability of serious cardiovascular tromboembolic and gastrointestinal adverse events.