A robustness analysis procedure is applied to the control of tubular fixed-bed reactors. The analysis utilizes a generalized uncertainty description to allow for zero or pole migration across the imaginary axis, in an attempt to reduce conservatism associated with such robustness tests. The tubular reactor control consists of critical modeling steps which have to be accounted for during the controller design phase. The impact of model reduction and parametric uncertainty is discussed within this framework and a suggested controller design is evaluated on the basis of robustness.