Primary progressive multiple sclerosis (MS) is a chronic demyelinating degenerative disorder of the central nervous system. The most common presentation is with a spastic paraparesis, which may be asymmetrical. In contrast to relapsing remitting MS, discrete attacks are not a characteristic feature and the temporal course is of gradual symptomatic deterioration. The current diagnostic criteria are based on this clinical phenotype, with supportive evidence from magnetic resonance imaging, and examination of cerebrospinal fluid and visual evoked potentials in some cases. At present, there is no effective disease modifying therapy, but a wide range of symptomatic treatments are available. These may be of great benefit to individual patients and include pharmacological measures, multidisciplinary therapist input and neurorehabilitation. New treatments which target neurodegeneration and promote brain repair are required, and research in these areas offers hope for the future.