This paper outlines the application of the magmatic phase determination and related techniques of zircon research in the investigation of 9 zircon specimens separated from Variscan granites from the Cierna Hora Mts. (Western Carpathians). Three types of data originating from zircon study lead to a more precise determination and discussion of the genesis of granitic rocks: morphological data, geochemistry of trace elements and internal structure of zircon crystals. The morphometrical properties of specimens from the Miklusovce Complex indicate the pronounced peraluminous character of the melt. The zircon data from specimens TI, TII and SK, SP seem to reflect two series of events in the development of the Bujanova Complex. In the case of the Lodina Complex the analysed data indicate anatectic conditions.