A process for the preparation of (co)polymers of conjugated dienes which comprises polymerizing at least one conjugated diene in the presence of a catalytic system comprising at least one bis-imine-pyridine complex of cobalt having general formula: wherein: - R 2 and R 3, equal to or different from each other, represent a hydrogen atom; or they are selected from linear or branched C 1 -C 20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; - R 1 and R 4, different from each other, represent a hydrogen atom, or they are selected from linear or branched C 1 -C 20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted, arylalkyl groups; - or R 1 and R 2 can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - or R 3 and R 4, can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - R 5, R 6 and R 7, equal to or different from each other, represent a hydrogen atom; or they are selected from linear or branched C 1 -C 20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted, arylalkyl groups; - or R 5 and R 6, can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - or R 6 and R 7, can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - X 1 and X 2, equal to or different from each other, represent a halogen atom such as chlorine, bromine, iodine; or they are selected from linear or branched C 1 -C 20 alkyl groups, -OCOR 8 groups or -OR 8 groups wherein R 8 is selected from linear or branched C 1 -C 20 alkyl groups. - R 2 and R 3, equal to or different from each other, represent a hydrogen atom; or they are selected from linear or branched C 1 -C 20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; - R 1 and R 4, different from each other, represent a hydrogen atom, or they are selected from linear or branched C 1 -C 20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted, arylalkyl groups; - or R 1 and R 2 can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - or R 3 and R 4, can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - R 5, R 6 and R 7, equal to or different from each other, represent a hydrogen atom; or they are selected from linear or branched C 1 -C 20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted, arylalkyl groups; - or R 5 and R 6, can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - or R 6 and R 7, can be optionally bound to each other to form, together with the other atoms to which they are bound, a cycle containing from 3 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally substituted with linear or branched C 1 -C 20 alkyl groups, said cycle optionally containing other heteroatoms such as oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; - X 1 and X 2, equal to or different from each other, represent a halogen atom such as chlorine, bromine, iodine; or they are selected from linear or branched C 1 -C 20 alkyl groups, -OCOR 8 groups or -OR 8 groups wherein R 8 is selected from linear or branched C 1 -C 20 alkyl groups.