Carrier mobility is an important parameter that defines the application of semiconductor materials. In considered structures, the main mechanisms that limit mobility are scatterings by longitudinal optical (lo) phonons, by acoustic (ac) phonons and by impurities.  The relaxation time τ as a function of carrier energy ε has the periodical form [1] when electrons are only scattered by lo phonons. Here it is presented a theoretical research of temperature and density mobility dependences in PbTe/PbEuTe quantum well (QW) structures. All calculations are carried out in the interval of temperatures 20 K ≤ T≤400 K and for electrons density n≤ 5·1019 cm-3.  Also, it is examined whether the above mentioned relaxation time peculiarity shows in these dependences or not.             The research is based on the models of rectangular QWs, which are oriented parallel to (100) and (111) planes. The well's width is taken as 20Å. The models take into account the temperature dependences of confinement potential, of the energies Eα of αth level of dimensional quantization and of dispersion law. Carrier transport along wells is considered on the base of Boltzmann equations, which are solved by iterations method. The details of calculation can be found in [2]. The impurity scattering is taken into account using the model where randomly distributed impurities are disposed in the well, and screening is calculated in random phase approximation and long-wavelength limit. The research shows that impurity scattering gives appreciable contribution at T≤30 K. It is found that mobility dependences μ(T) are similar to corresponding dependences in the bulk. The dependence  μac(T) has power character  μac~T -p where power-law index p is a little greater than 1 due to carrier confinement in z direction and non-parabolic dispersion law. The dependence  μlo(T) is described mainly by the factor exp(ħω0/k0T ), where  ω0  is the frequency of lo phonon. For T≥50K, the scattering by lo and ac phonons gives comparable contribution into mobility. At T=20K, the scattering by ac phonons and impurities are the only mechanisms that play a role. At high T and n≤ 5·1019 cm-3, the mobility does not depend on carrier density.  The peculiarities of  τ(ε) is most expressed in μ(n) at T ~77 K  (see Fig. 1 and Fig. 2). In general, the dependence  μ(n) is similar to τ(ε) when electron gas is degenerated. To become apparent periodical structure of  τ(ε)  in   μ(n), it is necessary lower temperatures  k0T<< ħω0 . However, the lo phonon scattering is not essential at these temperatures in considered structures.