The capability of 1-D models in simulating multitubular catalytic fixed bed reactors at industrial scale is evaluated. To this end, several recent studies comparing the results of 1-D models with the assumed accurate estimations obtained from 2-D models are discussed. It is shown that the key factor to reach satisfactory results is the evaluation of the overall heat transfer coefficients. There are available at present suitable expressions to approach this requirement. They are based on the basic thermal parameters of the heterogeneous 2-D model (2H model). The heterogeneous 1-D model (1H model with overall heat transfer coefficients including the effect caused by the dependence of reaction rate upon temperature (δ_r effect) behaves much in the same way as the 2H model, even at critical conditions for parametric sensitivity, while saving a considerable amount of computational effort. Owing to the significance of overall heat transfer coefficients, a brief discussion about existing correlations to estimate the basic thermal parameters is also carried out. From this revision along with an analysis of sensitivity, the expected error in reactor simulation is evaluated, and ranges of operating and geometrical variables leading to higher levels of uncertainty are detected.