Recent marine magnetic data analysis, bathymetric data, and ODP Leg 170 age determinations from the Cocos Plate off Costa Rica prove that both the Cocos and the Malpelo ridges in the Eastern Panama Basin belong to an abandoned spreading system as opposed to the current interpretation as an aseismic hotspot track. The Cocos Plate separated from the Farallon/Pacific Plate at 21 Ma and sudden jumps of the spreading ridges occurred at 19 and 15 Ma. Two arrays of NE-SW and ENE-WSW striking magnetic anomaly patterns were identified in the area of the Cocos and Malpelo ridges. Bathymetric data of the same area reveal graben structures on top of both ridges which parallel the magnetic patterns. ODP Leg 170 determined a bio- and magnetostratigraphic age of 16.4 Ma in sediments directly overlying a doleritic sill at the base of the sedimentary section of the Cocos Plate assigning a lithospheric age of about 17-20 Ma at sites off the Nicoya Peninsula, northwestern Costa Rica. These results can neither be reconciled with the interpretation of the Cocos Ridge as an aseismic hotspot ridge formed by the Galapagos hotspot nor with the predicted crustal age of the Cocos Plate of 25-28 Ma from current plate tectonic models. A palinspastic reconstruction of the Cocos-Malpelo spreading system at 19 Ma ago relocates the Malpelo Ridge into a position in prolongation of the Cocos Ridge. The missing part of about 300-350 km of the Cocos-Malpelo spreading ridge has already been subducted beneath the Middle American landbridge. Assuming a constant subduction rate of about 80 mm per year over the last 18 million years the onset of the Cocos Ridge indentation into the Central American landbridge started about 4 Ma ago. It is responsible for a strong uplift in Central and Southern Costa Rica. We conclude that the Cocos and Malpelo ridges belong to an abandoned spreading system which was active from 18 to 15 Ma rather than a hotspot track formed by the Galapagos hotspot. The Cocos Plate originated as an independent plate tectonic unit with the onset of spreading at the Cocos-Malpelo spreading system 21 Ma ago.