In this work, the structural and magnetic properties of Co1-xZnxFe2O4 (0.0 <= x <= 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co-Zn ferrite nanoparticles prepared by sol-gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co-60 gamma-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co-Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (alpha) and other structural parameters of gamma-irradiated and un-irradiated Co1-xZnxFe2O4 spinet ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n(B)) etc. magnetic parameters were increased after irradiation. (C) 2014 Elsevier Ltd. All rights reserved.