A draper seal for a crop harvesting header is provided. The header includes a forwardly disposed cutter bar assembly and a rearwardly disposed draper deck assembly. The draper seal includes a flexible strip that runs parallel to the cutter bar assembly and perpendicular to the direction of travel. A bracket secures the forward edge of the flexible strip to an upper surface of the cutter bar assembly, which bracket also biases a rearward edge of the flexible strip into engagement with an upper surface of the draper deck assembly, thereby creating a seal between the cutter bar assembly and the draper deck assembly.