Magnetization studies were carried out for the novel FeSe1−xTex superconductors ( 0 ≤ x ≤ 1 ) to investigate a behavior of the intrinsic magnetic susceptibility χ in the normal state. The magnetic susceptibility was found to increase gradually with Te content. The temperature dependencies of the magnetic susceptibility χ and its anisotropy Δ χ = χ ∥ − χ ⊥ were measured for FeSe in the temperature range 4.2–300 K, and a growth of susceptibility with temperature was revealed. For FeTe a substantial increase of χ under pressure was found. Ab initio calculations of the band structure and magnetic susceptibility have shown, that FeSe1−xTex systems are close to magnetic instability with dominating enhanced spin paramagnetism. The calculated paramagnetic susceptibility exhibits a strong dependence on the unit cell volume V and especially the height of chalcogen species from the Fe plane. With appropriate values of these parameters the calculations have reproduced the experimental data on χ ( T ) and χ ( P ) for FeSe and FeTe, respectively.