The solid-solid interactions between pure and lithium-doped magnesium and ferric oxides have been investigated using DTA and X-ray diffractograms (XRD) techniques. Equimolar proportions of basic magnesium carbonate and alpha -Fe2O3 were employed and lithium was added as lithium nitrate. The amounts of dopant were 0.75, 1.5, 3 and 6 mol% Li2O. The results obtained showed that the addition of small amounts of lithium nitrate to the reacting mixed solids much enhanced the thermal decomposition of magnesium carbonate to an extent proportional to its amount added. The addition of 12 mol% LiNO3 decreased the decomposition temperature Of MgCO3 from 525.5 to 362 degreesC. MgO underwent solid-solid interaction with Fe2O3 at temperatures starting from 800 degreesC yielding MgFe2O4. The amount of ferrite produced increased when the precalcination temperature of the mixed solids was increased. However, the completion of this reaction required prolonged heating at elevated temperature > 1100 degreesC owing to the formation of MgFe2O4 phase which covered the surfaces of the grains of each solid, thus, hindering the diffusion of Mg2+ and Fe3+ ions. Doping with Li2O Much enhanced the solid-solid interaction between the mixed oxides to an extent proportional to the amount of Li2O added leading to the formation of MgFe2O4 phase at temperatures starting from 700 degreesC. The addition of 6 mol% Li2O to the mixed solids followed by precalcination at 1050 degreesC for 4 h resulted in complete conversion of the reacting oxides into magnesium ferrite. The promotion effect of Li2O towards the ferrite formation was attributed to an effective increase in the mobility of the various reacting cations. The activation energy of formation (AE) of magnesium ferrite was determined for pure and variously doped solids and the values obtained were 203, 126, 95 and 61 U mol(-1) for pure mixed solids and those treated with 1.5, 3 and 6 mol% Li2O, respectively.