Several subduction and collision stages have been recognized in the evolution of the Kokchetav massif based on recent and already published geological and geochronological data. Their related subduction and collisional zones were formed during the subduction of a lithospheric plate of the Paleo-Asian Ocean comprising the Kokchetav microcontinent under the Ishim Vend-Cambrian island arc and then under the Stepnyak Ordovician island arc. Subduction of the Kokchetav microcontinent under the island arc resulted in formation and further exhumation of high-pressure and ultrahigh-pressure (HP and UHP) rocks. A part of the microcontinent submerged to depths of 150-200 km, where the rocks experienced HP and UHP metamorphism, partially melted and then were squeezed out to the surface simultaneously with the continuing subduction. The collision continued in Late Cambrian-Tremadoc time and resulted in the blockage of the subduction zone and deformation of exhumed HP and UHP rocks within the accretionary wedge. The subduction zone then jumped toward the back part of the microcontinent to form the Stepnyak island arc and back arc basin. The microcontinent rocks, island-arc and accretionary wedge units were thrust over the Stepnyak back-arc basin in Middle Ordovician time. Sheets and blocks of HP rocks occur within two structural units: megamelange belt and accretionary prism. The megamelange belt consists of two tectonic units. Unit 1 comprises UHP rocks - eclogites and diamondiferous metamorphic rocks and eclogite lenses hosted by mica schists. Unit 2 - eclogite-bearing mйlange - consists of several tectonic sheets respectively composed of layered gneisses with eclogite, garnet schists and granite-gneisses. The age of eclogite is 535 Ma and the age of rocks separating the tectonic sheets is 519-490 Ma. The megamelange belt includes different segments of the microcontinent, its sedimentary cover and oceanic rocks reflecting different levels of subduction.The accretionary prism comprises deformed tectonic sheets consisting of Cambrian olistostromes, turbidites, island-arc volcanogenic-sedimentary rocks, gabbro, gneiss and basalts. The age of muscovite and amphibole from the schists separating accretionary units is 475 Ma (Ar-Ar and K-Ar). The deformed megamelange and accretionary sheets are thrust over the Stepnyak basin. The thrust zones contain 465-440 Ma chlorite-muscovite schists. This study was funded by RFBR grants nos. 02-05-64627 and 03-05-64668.