Abstract We have studied the fragmentation and aggregation of C60 and its radical adducts RnC60 by laser-desorption TOF mass spectrometry in the positive and negative ion channels. The mechanism of the formation of daughter fullerenes in the negative ion channel and the enhancement of fullerene aggregation products have been discussed. We consider that the electron transfer process between neutral cage-like clusters and the radicals is responsible for the appearance of strong mass peaks of daughter fullerene anions in the case of C60 radical adducts. The effects of the radicals on the fullerene aggregation process have been discussed.