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-imino-pyridine complex of cobalt having general formula (I): wherein: R2 and R3, equal to or different from each other, represent a hydrogen atom; or they are selected from linear or branched C1-C20 preferably C1-C15, alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; R1 and R4, different from each other, represent a hydrogen atom; or they are selected from linear or branched C1-C20 preferably C1-C15, alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; arylalkyl groups; or R1 and R2 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 C1-C20, preferably C1-C15, alkyl groups, said cycle optionally containing other heteroatoms such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; or R3 and R4, 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 C1-C20, preferably C1-C15, alkyl groups, said cycle optionally containing other heteroatoms such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; R5, R6 and R7, equal to or different from each other, represent a hydrogen atom, or they are selected from linear or branched C1-C20, preferably C1-C15, alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted; aryl groups optionally substituted; arylalkyl groups; or R5 and R6, 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 C1-C20, preferably C1-C15, alkyl groups, said cycle optionally containing other heteroatoms such as, for example, oxygen, -sulfur, nitrogen, silicon, phosphorous, selenium; or R6 and R7, 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 C1-C20, preferably C1-C15, alkyl groups, said cycle optionally containing other heteroatoms such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; X1 and X2, equal to or different from each other, represent a halogen atom such as, for example, chlorine, bromine, iodine; or they are selected from linear or branched C1-C20, preferably C1-C15, alkyl groups, -OCOR8 groups or -OR8 groups wherein R8 is selected from linear or branched C1-C20/preferably C1-C15, alkyl groups.