Developing novel contrast agents for efficient MRI sensitivity is very essential for early diagnosis of cancer. In the present work, we have prepared novel, eco-friendly, non-toxic iron oxide nanoparticles (IONPs) as efficient MRI contrast agents. Earth abundant magnetite sand was used for the preparation of IONPs using acid leaching method. Further, co-precipitation method was used to obtain fibrin functionalized iron nanoparticles (F-IONPs). The nanoparticles were crystalline in nature with average size distribution values as 15 nm and 35 nm for IONPs and F-IONPs respectively. Haemolysis and MTT assay proved the biocompatibility of the prepared nanoparticles with their distribution across the cytoplasm and nucleus in NIH 3T3 cells. Moreover, MRI and VSM results revealed the magnetic property of F-IONPs, with the magnetic saturation value of 51.7 emu g(-1). Thus, F-IONPs with good cytocompatibility and high magnetic property can serve as a novel platform for enhanced MRI sensitivity and drug delivery. (C) 2014 Elsevier B.V. All rights reserved.