CCD observations in the Johnson V, Kron-Cousins I and the Washington system C and T_1_ passbands have been used to generate colour-magnitude diagrams (CMDs) reaching down to V~21.0mag and T_1_~19.0 for Trumpler 5, an old open cluster located towards the Galactic anticentre. Our data analysis confirms the existence of non-uniform extinction over the face of the cluster, the mean E(V-I) and E(C-T_1_) values being 0.80+/-0.05 and 1.17+/-0.15, respectively. Through comparison of the cluster CMDs with theoretical isochrones of the Geneva group, Washington Standard Giant Branches and measures of V and T_1_ indices, we derive the following values for the cluster apparent distance modulus, age, and metallicity: V-M_V_=13.80+/-0.30 (corresponding to a distance from the Sun of 2.4+/-0.5 kpc and 0.04kpc above the Galactic plane), t=5.0+/-0.5Gyr and [Fe/H]=-0.30+/-0.15. We estimate the cluster angular radius to be about 7.7 arcmin (=5.4pc) from star counts carried out within and outside the cluster field.