This paper considers the analysis and controller design for the ALSTOM gasifier system. The inherent properties of this highly coupled and numerically ill conditioned multivariable system are studied. Minimal realizations of the system models at the three operating points to be considered are determined, and the numerical conditioning of the system is improved. Model order reduction methods are applied to simplify the subsequent design. A controller is designed using the LQG with LTR technique at the 100 per cent load condition, and the robustness of this controller at other load conditions is assessed. No violation in the desired performance specifications was encountered.