Paramagnetic asphaltene on the surface of the Co-rich amorphous ribbon (Fe5.85Co70.15Mo4B15Si5) samples, 13 mm in length and 5 mm in width, was grown in order to improve the GM! response. GMI response was measured over a frequency range of 0.1 to 3.5 MHz and under a static magnetic field. The asphaltene coating process leads to the increase of GMI effect more than 4.8 times compared to the uncoated sample at 2.0 MHz. To our knowledge, such a GMI enhancement is reported for the first time by asphaltene coating process. It is believed that such an increase in GMI response will be important in practice due to their applications in electronic devices-specially, magnetic field sensors and future magnetic recording heads. The results are compared with other studies.