We report on the epitaxial growth and physical properties of spinel MnFe 2 O 4 (111) thin films with thicknesses down to 2 nm. The thin films, grown on α-Al 2 O 3 (0001) single crystals or Pt(111) buffer layers by oxygen-assisted molecular beam epitaxy, exhibit high structural order with sharp interfaces and low roughness. The electrical and magnetic properties are carefully investigated and it is shown that MnFe 2 O 4 (111) ultrathin films keep an insulating and ferrimagnetic behavior at room temperature. Special attention is given to the iron/manganese valence state and the cationic ordering. X-ray absorption spectroscopy and magnetic circular dichroism measurements reveal that thin films contain mainly Fe 3+ and Mn 2+ cations, distributed predominantly in a normal spinel structure. This study proves the high potential of MnFe 2 O 4 to be used as a magnetic tunnel barrier for spin filtering applications at room temperature.