The incorporation of CoCl2 and FeCl2 into polyacrylonitrile (PAN) modified the carbonization behaviour and led to the development of carbon with a narrow pore radius ranging from 1.8-2.3 nm and a high surface area ranging from 182-190 m(2) g(-1). The carbon obtained was of better structural organization than from the original PAN, having an interlayer spacing, d(002), of 0.342 nm and a crystallite dimension along the c-axis, L(c), of 5.5-8.5 nm. The transition metals incorporated into carbon exhibited a strong resistance to hydrochloric acid solution treatment, suggesting high dispersion and strong anchoring of the transition metals in the carbon matrix. These non-crystallized and homogeneously distributed transition metals in carbon seem to promise some interesting applications, for example as supports in catalysis.