The changes in some biochemical and haematological parameters in three cows with post-parturient haemoglobinuria were described. The animals were 4, 6, and 7 years of age. These cows had calved in the autumn. Post-parturient haemoglobinuria in the cattle occurred at a post-partum of about 3 weeks. The cows received phosphorus supplementation and supportive treatment. The mean serum phosphorus level in the affected cows was significantly lower compared with healthy cows. In the meantime, the blood RBC, PCV, MCHC, and Hb values were also significantly lower compared with healthy cows. In conclusion, the deficiency of phosphorus could be responsible for the development of post-parturient haemoglobinuria in the cows.