Hydranth, hydrotheca and gonangium structure and morphology of Obelia bidentata Clark, 1875, specimens collected from Port Said, Egypt, is found to be similar to that of other specimens collected elsewhere in the world. The present materials are characterised by oblique hydrothecal diaphragm and truncated gonotheca with no obvious aperture. Blastostyle carrying the medusa buds was observed to force its way through the apical gonotheca wall to release the medusae. Spatial distribution of the polyp ciliate epibionts was investigated as well. The largest number of ciliate epibionts was found on the hydrotheca followed by hydrocaulus then the hydroriza, while the lowest was found on hydrothecal pedicel. Species of the genera Cothurniopsis and Vaginicola were recorded for the first time as hydroid epibionts.