Garzón Posada A.O., F.E. Fajardo Tolosa, D.A. Landínez Téllez, J. Roa-Rojas, G. Peña Rodríguez. Synthesis, electrical and structural characterization of a composite material based on powdered magnetite and high density polyethylene. Rev. Acad. Colomb. Cienc., 37 (1): 55-59, 2013. ISSN 0370-3908. This work describes the synthesis and characterization of a composite material based on magnetite filled HDPE, which is comrnonly known for its magnetic properties. Composites of this kind are used in different applica­tions such as magnetic and microwave absorption, transducers manufacturing, and biomedical applications like targeted drug delivery, organs tagging, etc. The samples were produced according to different volume ratios of magnetite and HDPE. The samples structure was analyzed through X-ray diffraction tests and the crystallinity degree was calculated. Then, the samples were electrically characterized through volume resistivity measure­ments. The results showed that for ratios less than the 20% of magnetite there is not a substantial reduction in the resistivity ofthe composite compared to the unfilled HDPE. For magnetite ratios above the 30% the com­posite shows a substantial reduction of six orders of magnitude in its electrical resistivity.