Although inequalities in health between the most affluent and most deprived individuals in our communities have been well documented, the underlying causes are still not completely understood. There has been recent interest in the contribution of multiple morbidity as one explanatory factor, although there is little evidence as yet regarding this. The few general practice based studies investigating the presence of comorbidity have highlighted its significance. However the relationship between multiple morbidity and deprivation is still relatively under-researched and under-reported in the literature. As a result, the full extent of comorbidity and its implications remains unknown. Some argue, however, that there is now recognition that comorbidity is the rule rather than the exception and that this ought to influence approaches to quality of care. If this is to take place there is an urgent need for a greater understanding of the nature and impact of comorbidity.