FIELD: medicine; pharmaceutics; production of medicinal lyophilized and phosphamide compositions. SUBSTANCE: lyophilized composition producing cytostatic antitumoral effect contains urea in the amount from about 0.3 to 5 wt. p. per 1 wt.p. of phosphamide and additionally 0.1-1 wt.p. of sodium 2-mercaptoethane sulphonate per each wt.p. of phosphamide. Method resides in freezing aqueous solution containing urea and phosphamide down to temperature about minus 40 C, followed by sublimating it within temperature range from minus 40 C to plus 28 C and under pressure within range from about 0.7 Torr (0.093296 kPa) to about 0.1 Torr (0.013328 kPa). EFFECT: enhanced thermal stability end extended shelf storage life. 10 cl, 2 tbl
