Ternary oxides, RCoO3 (S) (R = La, Nd, Sm Eu, Gd, Tb, Dy and Ho), have been prepared by citrate-nitrate gel combustion route and characterized by X-ray diffraction analysis. Heat capacities of these compounds have been measured in the temperature range from 130 to 850 K using a heat flux type differential scanning calorimeter. Heat capacity versus temperature plots for these compounds indicated broad humps in the temperature range from 450 to 780 K suggesting electronic transitions in these compounds accompanied by large entropy increments. The transition temperatures showed increasing trend with decrease in ionic radii of the lanthanide ion. (C) 2007 Elsevier B.V. All rights reserved.