An oil adsorbent comprising natural fibers the surface of which is coated with a water-repellent paraffin layer which is in turn coated with an elastic rubber layer. The adsorbent is manufactured by treating the surface of the natural fibers with a paraffin emulsion, drying the fibers to form a water repellent paraffin layer thereon, treating the product with a latex, and then curing the latex to form an elastic rubber layer on the paraffin layer. The oil adsorbent has such advantages that it floats on the surface of water stably for a long period of time retaining its original form, that the contained paraffin is not back extracted by adsorbed oil and that it does not cause any trouble on burning.