In this study, the performance of magnetite-montmorilonite composites in absorbing Co2+ and Cd2+ composites made from Pacitan bentonite and natural iron ore reported. Composites are synthesised by inserting iron oxide into the interlayer of bentonite and then calcined at 400 °C for 1 hour. magnetite formed in the interlayer gallery of bentonite has a magnetite structure and high thermal stability. The adsorption of Co2+ and Cd2+ cations was carried out in aqueous solution by batch method at various initial pH variations, contact time, and initial concentration of the solution. The results showed that the two metal cations were absorbed maximum at pH 5 in contact time of 10 minutes for Co2+ and 105 minutes. The maximum concentration of Co2+ that can be absorbed occurs at 50 ppm and 70 ppm for Cd2+. Adsorption of the two cations follows the Langmuir adsorption isotherm pattern with an R2 of 0.945 for Co2+ and 0.995 for Cd2+. The adsorption energy of Co2+ adsorption is -23.42 kJ / mol and -32.45 kJ / mol for Cd2+.