The effect of acid-base properties of three different supports (hydroxyapatite, gamma-Al2O3 and MgO) and of the redox properties of dispersed Ru or Ni on the catalytic conversion of ethanol into butanol has been investigated. Catalytic tests have been carried out in the temperature range 200-500 degrees C by feeding an ethanol/N-2 mixture to a lab-scale fixed bed reactor of powdered catalyst. Both supports and metal containing materials were deeply characterized by XRD, N-2 physisorption, CO2 and NH3 TPD, H-2 TPR. Highest butanol yields were associated to low ratio between acid and basic centres, typical of MgO, and to the easy reducibility of well dispersed metals as well. Good butanol yields can be also ascribed to the enhancement of both surface area and basicity of MgO provided by metal addition.