Abstract: A multiple core hose comprises a plurality of discrete hose assemblies, each including a primary hose formed from a flexible synthetic plastics material, having a fluid passage extending generally longitudinally therethrough, and a plurality of generally longitudinally extending recesses adapted to seat secondary hoses; a plurality of secondary hoses formed from a flexible synthetic plastics material, seated in the primary hose recesses, the secondary hoses having fluid passages extending generally longitudinally therethrough in heat transfer relation with the primary hose passage; and a flexible tubular sheath of a thermally insulating material, the primary/secondary hose assemblies being assembled together, side-by-side, with the seated secondary hoses disposed around the primary hose passages, within the sheath.