Pitting corrosion of titanium, studied under potentiostatic conditions, is only occurring at high potentials in halide aqueous solutions; valence of dissolution of titanium in pits is about 4. Pits growth kinetic can be described by i = kt n laws (n = 1,5 for the main stage of growth). Metallographic examination of pits associated with these results leads to propose a geometrical model of pits growth. Pits with hemispherical cap shape are growing under a passive film the nature of which, probably saline, should ascertain the polygonal edges of some pits by anisotropic dissolution of the film. On non anodically passivated titanium, interstitial or crevice type pitting corrosion observed on passivated surfaces, is occurring with increased sharpness.