Calculations of neutron escape probability from a homogeneous isotropically scattering slab of finite optical thickness are reported as obtained by solving exactly the stationary linear integral transport equation for the total flux of monoenergetic neutrons. This is done for both critical and subcritical configurations of the slab under examination, with both constant and variable sources being referred to in the latter configuration. Due to the transport approach here used, the numerical results for the escape probability cover the full range of variation of the mean number of scattered neutrons per collision, cs, i.e., 0 ≤ cs ≤ 1, whereas the half-thickness of the slab considered ranges from 5 or 10 mean-free-paths down to values as small as 10-4 mean-free-paths.