This chapter has outlined the reasons for the development of marked elevations of triglycerides that can be associated with the chylomicronemia syndrome. The clinical features of the syndrome have been discussed, with particular emphasis on chylomicron-induced pancreatitis, since this can be life-threatening. An approach to the diagnosis and management of this syndrome has been provided, with emphasis on the need for long-term follow-up and compliance to keep plasma triglycerides to a reasonable level and thereby avoid recurrent clinical complications due to chronic chylomicronemia.