After a review of the literature on titanium production under plasma conditions, the main parameters controlling the reactions (residence time, type and relative quantity of reducer, reaction temperature, etc.) are emphasized. The controlled-atmosphere chamber where the rutile or anatase particles are heated and partly reduced in a crucible by a d.c. plasma torch with Ar-H2 as plasma gas is described. Study of the temperature dependence of the Gibbs free energy allows one to explain, at least qualitatively, the experimental results obtained which correspond at best to 10% (weight) of TiO2 reduced to TiO by carbon.