Cobalt ferrite CoFe 2 O 4 nanoparticles were prepared via a polyacrylamide gel route and were characterized by XRD, SEM, XPS and VSM. It is demonstrated that the sample (designated S1) prepared without using the cross-linking agent bis-acrylamide has an average grain size of 45 nm, while the sample (designated S2) prepared by introducing an amount of bis-acrylamide which is about 1/5 times the amount of acrylamide has an average grain size of 23 nm. The two kinds of particles are shaped like spheres. The cation distribution is determined, from Co 2p 3/2 and Fe 2p 3/2 XPS spectra, to be (Co 0.4 Fe 0.6 )[Co 0.6 Fe 1.4 ]O 4 for both the samples, where (Co 0.4 Fe 0.6 ) and [Co 0.6 Fe 1.4 ] represent cations in the tetrahedral and octahedral sites, respectively. Magnetic measurement reveals a saturation magnetization of 67.3 A·m 2 ·kg ¹1 for sample S1 and 62.3 A·m 2 ·kg ¹1 for sample S2, but a similar coercivity of about 87.5 kA·m ¹1 for both the samples. [

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