Polyurethane urea (PUU) was synthesized using macrochain extenders of 2-(2-aminoethoxy)ethan-1-amine (DA1) and 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propan-1-amine (DA3) at a molar ratio of 4,4'-diaminodiphenylmethane (DADP) to DA1 and DA3 as 30:70; 50:50; and 70:30. The tensile strength () of PUU is in the range of 0.74–2.21 MPa, and the relative elongation at break () is 27.4–1003%. According to the DSC method, the studied PUUs are single-phase systems. The glass transition temperature (Tg) of the PUU DA1 series is from 21.920C to –39.480C, and the glass transition temperature for the PUU DA3 is from –20.040C to –33.960C. Based on the synthesized PUUs, composite materials were prepared containing 1 wt.% of ifosfamide (IFO) (=0.74–2.21 MPa, and =31.8–276.3%). According to the results of thermophysical studies, the compositions with IFO are single-phase systems with Tg of –24.80C to –36.220C. Thus, the introduction of IFO into the composition leads to an increase in the packing density of the macrochain, a decrease in the size of the free volume and, consequently, a decrease in the mobility of the blocks in space and a decrease in Сp. Compositions with IFO are resistant to temperatures of ~2500C, which allows thermal sterilization before use. Using the HPLC-UV method, the dynamics of IFO release from samples of PUU compositions synthesized at a molar ratio of DADP:DA1 as 0.5:0.5 and DADP:DA3 as 0.7:0.3 was investigated. It was established that IFO is released within 60 days from compositions based on PUU DA3 in the amount of 29.6%, and from compositions based on PUU DA1 in the amount of 42% with respect to the total amount of IFO introduced. The resulting composites are promising materials for medicine as means of local prolonged therapeutic action.