Two series of ethylene-propylene copolymers were synthesized in the whole composition range using a metallocene catalyst, one in the homogeneous phase (H copolymers), and the other with the catalyst supported in silica (S copolymers). Some differences were found between the two groups. Therefore, the amount of ethylene needed to obtain a certain proportion of the ${gamma}$form is lower in the H than in S series. Moreover, the composition to obtain the pseudo hexagonal form is also different for the two groups. On the other hand, degree of crystallinity, crystal sizes and microhardness values display a similar variations with the comonomer content of the two series. Consequently, from a macroscopic point of view, materials with similar macroscopic mechanical properties can be produced using both supported and homogeneous metallocene catalysts despite the structural differences.