The aim of this study was to investigate the effectiveness of the per os marking method of otoliths in burbot at different early life stages. In experiment E1 burbot larvae 12 (DPH) and in E2 -22 (DPH) were fed with live Artemia salina nauplii immersed in alizarin red S (ARS) and tetracycline hydrochloride (TC), for 1, 3, or 6 subsequent days (in E1) and for 1, 4, or 8 subsequent days (E2). In experiment E3 the marking procedure involved feeding burbot juveniles (92 DPH) using a commercial feed supplemented with ARS at a doses of 0 to 100 g per kg of feed. In E1, the highest percentage of marked otoliths was recorded in the group fed for 6 days with A. salina immersed in TC. During E2, 100% of marked otoliths were recorded in the groups fed for 4 or 8 days, regardless of the type of dye used. The highest percentage of marked otoliths in E3 was noted in the group fed with 40 g ARS/kg feed. In conclusion, for mass marking of burbot using the per os method, feeding larvae at 22 DPH with ARS-immersed A. salina nauplii continuously for 4 days is recommended for fishery practice.