There are five approved, partially effective, parenteral disease-modifying therapies for multiple sclerosis (MS), including three interferon-β preparations, glatiramer acetate and the antineoplastic agent mitoxantrone. A sixth drug, natalizumab, was withdrawn from the market in 2005 but could return with increased safety measures. Careful surveillance for, and management of, the minor and serious adverse effects associated with these therapies in routine practice provides the best opportunity for maintaining compliance and achieving maximal therapeutic efficacy. This review outlines the strategies for the prevention, identification and management of the complications associated with administration and ongoing use of current MS therapies. These skills will become increasingly important to those caring for MS patients as contemporary treatment regimens become increasingly complex.