A coil assembly for magnetic resonance imaging comprises a sheet (2) of flexible and stretchable dielectric material and at least one electrically conducting coil (4a, 4b) for receiving and/or emitting a radio frequency signal. The coil is attached to and extends along a face of the flexible sheet. At least part of the coil is made of a ribbon shaped braided conductor (6) that is arranged in substantially flat contact with the face.