In this paper the effects of tube rotation on heat transfer to a fluid flowing inside a tube are examined. The most pronounced influence is noted to be on the transition from laminar to turbulent flow region with lesser effects in the laminar region, and no measurable effects once the flow has become fully turbulent. Heat transfer data are presented for a wide range of through-flow and rotational Reynolds numbers. A brief examination of the flow by visual means revealed that tube rotation tends to stabilise laminar flow, and in fact can cause an already turbulent flow to revert back to a laminar flow. When the tube is rotating, the transition from laminar to turbulent flow as through-flow Reynolds number is sufficiently increased is characterized by a very distinct “burst of turbulence” phenomenon, photographs of which are presented in this paper.