© 2016 Inderscience Enterprises Ltd. This work was aimed to investigate the ability of iron nanoparticles in paraquat degradation using heterogeneous Fenton and photo-Fenton processes. The iron nanoparticles were synthesised and their sizes are in the nanometre range of 10-30 nm. SEM, TEM, and XRD were used to characterise the obtained materials. From XRD analysis and the Fe(II)/Fe(III) ratio, the iron nanoparticles are predominantly of magnetite phase. Results from Fenton reaction at pH3 show that paraquat with initial concentrations in range of 60-100 ppm has been degraded with the removal percentages in the range of 43.7-75.8%. In photo-Fenton process at pH3, the paraquat removal percentages were 70.9-99.1% for initial paraquat concentrations as of 100-300 ppm. The photo-Fenton reaction using iron nanoparticles provided higher efficiency in paraquat removal than the Fenton process. Results from this work can benefit further for application of iron nanoparticles in pesticides removal from water and wastewater.