A hinge rod retainer for a modular conveyor belt. The retainer retains a hinge rod within a passageway, while allowing room for rod expansion or contraction relative to the belt width. The retainer comprises a flexible portion and a support forming an outside edge of the modular conveyor belt. The flexible portion comprises a flexible hook including an opening for allowing passage of the hinge rod into the passageway. The flexible hook defines a trapping region between the passageway and outside edge of the modular conveyor belt for trapping a hinge rod end.