The objective of this research was to study the catalytic graphitization of cellulose fibers coated with iron oxide nanoparticles. Bleached cellulose fibers and iron oxide nanoparticles coated cellulose fibers were pyrolyzed at five elevated temperatures. The crystallographic structures of carbon-encapsulated iron oxide nanoparticles were then investigated by the following techniques: Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Raman Spectroscopy, Transmission Electron Microscopy (TEM), and Selected-Area Electron Diffraction (SAED). The graphitization of cellulosic fibers was enhanced by the presence of iron oxide nanoparticles. Moreover, iron oxide nanoparticles deposited on cellulosic fiber samples pyrolyzed above 800°C produced graphitic structures. TEM and XRD were performed to identify and characterize the phase transitions of carbon-encapsulated iron oxide nanoparticles after pyrolysis treatment at four temperatures: 500°C, 800°C, 1000°C, and 1600°C. TEM of samples pyrolyzed at or above 800°C showed resulting units were core-shell structures consisting of dark grains and a light matrix with graphitic structure.