We have the results of observations of 6 patients with parostal sarcoma, verified morphologically, which is approximately 5% of all patients with osteosarcomas that we have followed over the past 10 years. All patients were female, 2 of them were 25-26 years old, 4 were 35-40 years old. There is an opinion that older patients, in contrast to those suffering from other osteosarcomas, are characterized by a slower course of parostal sarcoma. At the same time, according to the Oncological Scientific Center of the USSR Academy of Medical Sciences, in 17 out of 25 patients with parostal osteosarcoma, the duration of the disease history before the first visit to the doctor was from 1 to 7 months. In patients 25-26 years of age, the duration of the anamnesis of the disease was 6-7 months. Women aged 35-40 years were observed without pronounced clinical complaints from 5 to 7 years.