Theoretical expressions are derived which describe the excess minority carrier distribution one can expect to observe when a Shockley‐Haynes measurement is performed in the presence of a contact. The contact has been modelled by postulating the existence of an interface recombination velocity (S) at the contact/semiconductor boundary. An ohmic contact (S= ∞) and the general case of a finiteScontact have both been considered. The variation in minority carrier distribution withSis illustrated using the derived expressions and the material parameters appropriate to a short wavelength (3–5 &mgr;m) Cadmium Mercury Telluride photodetector. The applied electric field (E) has been taken equal to 100 V cm−1and the width of the read‐out region,l= 40  &mgr;m. It has been shown that in this case an ohmic contact scarcely affects the average carrier distribution in the read‐out region, and therefore the ’’classical’’ theory can be applied to derive the mobility ( &mgr;) and diffusion constant (D), from the evolution with time of the conductivity modulation in the read‐out region. The same procedure, when applied to a less recombining contact, still leads to a fairly reliable value of &mgr;, but gives an appreciable overestimate ofD, due to the broadening of the observed pulse.