Selected biochemical values were determined in venous blood plasma from 45 clinically healthy ostriches (Struthio camelus) of different age and sex at an altitude 2 200 m above sea level. Animals were divided by age into 4 groups and the group of adults was divided by sex into 2 subgroups. Group 1 included chickens (n =10) aged 26.5 d; Group 2 included 70-day-old chickens (n =10); Group 3 were juvenile birds (n =8) aged 232.4 d; Group 4 was formed by 10 females and 7 males (n =17), aged 6 years old. The diet was a mixture composed of chopped alfalfa hay, sorghum and soybean meal, supplemented with vitamins and minerals. Drinking water and diet were provided ad libitum. In all blood samples 17 biochemical analytes were determined. Significant (P < 0.05) age effect was found in the values for glucose, uric acid, total protein, albumin, globulins, Ca2+, inorganic P, cholesterol, ALT, AST, creatine kinase, alkaline phosphatase and amylase. There was also a significant (P < 0.05) sex difference in values for total protein, albumin, globulins, Ca2+, Mg2+ and inorganic P. Blood biochemical values determined in this study can be considered reference data for disease diagnosis in ostriches of different ages. [ABSTRACT FROM AUTHOR]