Aim: The principal aim was to establish reference paediatric data for the serum homocysteine levels in Czech children and adolescents. Methods and Results: 144 children either healthy or not sufferig from acute or chronic inflammation, autoimmune disorders including rheumatic diseases, inflammatory musculoskeletal disorders, inflammatory bowel disease, diabetes mellitus, hypercholesterolemia, epilepsy, chronic renal failure, aged 0–19.9 years (0–6.9 years, n = 40; 7–10.9 y, n = 28; 11–15.9 y, n = 45; 16–19.9 y, n = 31) had their blood samples collected and the serum homocysteine level (S-homocysteine) was evaluated by chemiluminescence. A significant age dependence of the S-homocysteine levels was observed (R = 0.35, p < 0.01); with highest values of upper reference range in the 11–15.9 and 16–19.9 years’ group, respectively. Conclusion: The establishment of S-homocysteine reference Czech pediatric values is a potentially useful tool for proper evaluation of elevated homocysteine levels and corresponding risks in childhood., Vladimír Němec, Eva Bočkayová, Štěpán Kutílek, and Literatura 30