This paper aims to celebrate the important role of professor Giuseppe Dossetti as an active member of tbe Constituent Assembly, and his passionate political and legal commitment on the occasion of the centenary of his birth. First tries to highlight some correlations between the legal thought expressed by Dossetti during his lifetime with the constitutional scholarship, and then focuses upon Dossetti's attitudes and convictions concerning the ltalian republican Constitution that entered into force on 15/January 1948. He, in fact, had been a member of the Constituent Assembly with a lead role in the First Sub Commission in charge of drafting the section «the rights and duties of citizens» (1946-1947). During his parliamentary experience (1948-1952) he was actively involved in the political fight for 'the enforcement of the Constitutional text and worked to implement many reforms such as «La Cassa del Mezzogiomo». In the last years of his llfe (1994-1996), the old Founding Father was against the attempts of the ltalian Government to modify the republican Constitution and promoted the creation of committees for the defence of the same Constitution throughout ltaly.