This paper concerns H(infinity) control of systems under norm bounded uncertainties in all the system matrices. This is an extension of the work by Xie et al. where only the A matrix is allowed to be uncertain. It is found that the problem shares the same formulation with the H(infinity) control problem for systems without uncertainties. It can also be viewed as reducing the problem of dealing with systems with both structured uncertainties and unstructured uncertainties to one with unstructured uncertainties only.