The invention relates to improved ifosfamide preparations which are distinguished in that as primary auxiliary a polysaccharide, in general a glycan, preferably dextran, starches or cellulose, in particular dextrans having an MW of 20,000 to 85,000, modified starches such as hydroxyethyl starch and chemically modified celluloses such as hydroxyethylcellulose and sodium carboxymethylcellulose, a glycol ether, preferably polyethylene glycol, in particular polyethylene glycols having a molecular weight of 600 to 6000 or an amino acid, preferably alanine, leucine or glutamic acid, is added to them. The improved ifosfamide preparation can also contain as an auxiliary a pharmaceutically customary buffer, for example acetate, citrate or tris buffer, preferably phosphate buffer. In addition, improved ifosfamide preparations are obtained by addition of NaHCO.sub.3. The ifosfamide preparations according to the invention can comprise one or a combination of several auxiliaries. Mesna can be added to the formulation as a uroprotector.