Introduction: Cobas 6000 (Roche, Germany) is biochemistry analyzer for spectrophotometric, immu-noturbidimetric and ion-selective determination of biochemical analytes. Hereby we present analytical validation with emphasis on method performance judgment for routine operation. Materials and methods: Validation was made for 30 analytes (metabolites, enzymes, trace ele-ments, specific proteins and electrolytes). Research included determination of within-run (N = 20) and between-run imprecision (N = 30), inaccuracy (N = 30) and method comparison with routine analyzer (Beckman Coulter AU640) (N = 50). For validation of complete analytical process we calculated total error (TE). Results were judged according to quality specification criteria given by European Working Group. Results: Within-run imprecision CVs were all below 5% except for cholesterol, triglycerides, IgA and IgM. Between-run CVs for all analytes were below 10%. Analytes that did not meet the required speci-fications for imprecision were: total protein, albumin, calcium, sodium, chloride, immunoglobulins and HDL cholesterol. Analytes that did not fulfill requirements for inaccuracy were: total protein, calcium, sodium and chloride. Analytes that deviated from quality specifications for total error were: total pro-tein, albumin, calcium, sodium, chloride and IgM. Passing-Bablok regression analysis provided linear equation and 95% confidence interval for intercept and slope. Complete accordance with routine ana-lyzer Beckman Coulter AU640 showed small number of analytes. Other analytes showed small pro-portional and/or small constant difference and therefore need to be adjusted for routine operation. Conclusions: Regarding low CV values, tested analyzer has satisfactory accuracy and precision and is extremely stable. Except for analytes that are coherent on both analyzers, some analytes require adjustments of slope and intercept for complete accordance.