Two cases, mother and her son, suffering from acute poisoning with Tricholoma equestre were described. They had eaten 100-300 grams of this wild mushroom during nine consecutive meals. About 48 hours after the last meal containing the mushroom they developed fatigue, muscle weakness and myalgia, loss of appetite, mild nausea, profuse sweating. Maximal serum creatine kinase activity was 18,150 U/L in the mother and 48,136 U/L in the son. Maximal serum levels of aspartate aminotransferase and alanine aminotransferase were 802 U/L and 446 U/L, respectively, in the mother and 2002 U/L and 454 U/L, respectively, in the son. All routine biochemical tests were within normal range. No other causes of rhabdomyolysis such as parasitic, viral, immune diseases, trauma or exposure to medications were found. All the above mentioned symptoms and biochemical abnormalities disappeared within 23 days of hospitalization. Our observation confirms the results of Bedry and co-workers that Tricholoma equestre contains a toxin, which can cause rhabdomyolysis.