Contemporary sport requires a lot of effort from sportsmen, frequently exceeding their maximum physical and mental efficiency. Athletes often report poor dietary habits and reach for magnesium and vitamin B supplements to avoid dietary deficiencies. The aim of this study was to determine magnesium and vitamin B6 content in daily food rations of Polish athletes and to verify the justification of diet supplementation. Magnesium and vitamin B6 concentrations were determined in 62 collected and 12 reconstructed daily food rations of elite Polish runners. Flame atomic absorption spectrometry and HPLC methods were used for quantification of magnesium and vitamin B6, respectively. The analyzed female diets provided daily 256 +/- 111 mg of magnesium and 2.04 +/- 0.63 mg of vitamin B6 whereas male diets provided 284 +/- 58 mg of magnesium and 2.12 +/- 0.68 mg of vitamin B6. Computer analysis calculated 159-181% higher content o magnesium and vitamin B6 comparing to determined laboratory values. The results of this study indicate that in the analyzed daily food rations of athletes low magnesium intake was observed, thus diet supplementation with this mineral may be justified. Daily food rations fulfilled RDA for vitamin B6, thus supplementation with this vitamin was not justified.