Born in 1958 in Ath (Belgium), Olivier Dupuis is graduate in Social and Political Sciences at the University of Louvain, and member of the Radical Party since 1981, when he was committed into the campaign against the extermination by hunger and participated in several nonviolent actions which brought him several times to visit Brussels' police stations.

In 1982 he pursued a five-week hunger strike in support of the approval of a law known as "Survival Act", then passed by a large majority of the Belgian Parliament. Also in 1982 he was arrested and imprisoned for three days together with two other radical activists for distribution in Wentseslaw Sqare of pro-democracy leaflets for the right to life and the life of rights.

In September 1985 he was arrested in Dubrovnik, again detained for three days and then expelled for three years for having distributed, together with a dozen other radicals in Zagreb, Belgrade and the Dalmatian Coast, thousands of leaflets asking for the immediate adhesion of the then Yugoslavia to the European Community, as the only way of peaceful transition for that country.

A champion of anti-militarism, Dupuis considers both the military defence and the so-called alternative civil service as unable to face the real threats to peace and security, like the lack of democracy in Eastern Europe and non-respect of the right to life in Southern part of the planet. For these reasons he refused to serve the Belgian Army, and in October 1985 was arrested for desertion in front of Palace Berlaymont and sentenced to two years in prison, first in Saint-Gilles, then in Louvain. He was released after eleven months in jail and, as a substitution of punishment, he works for a couple of years for "Food and Disarmament" organization.

In 1987 Dupuis travels frequently Central and Eastern Europe, where the Radical Party struggles together with "Wolnosc i Pokoj" (Peace and Freedom) movement for the right to conscientious objection in Poland. During those period he co-operates with the information organs of the Radical Party.

At the end of 1988 he frequently visits Hungary in order to survey the possibility to hold in that country the Congress of the Radical Party, following the refusal of Belgrade's authorities. Hungarian authorities gave the permission for the Congress to take place in Budapest, in April 1989, and then Dupuis settled in the Hungarian capital, traveling Central Europe to organize the first radical groups while very seldom still were those believing in the possibility of the fall of the Iron Curtain.

In December 1991 - while under the pressure of France and England the European Community insists in not recognizing Yugoslavia's former republics -, together with Marco Pannella and other anti-militarist radicals Dupuis worn the Croatian uniform and went to the trenches surrounding Osijek, the Slavonic town risking the same fate of Vukovar.

During the period 1992-1994 Dupuis increases the activities towards parliamentarians in Central Europe, more and more numerous in joining the Radical Party, transnational and cross-divisional transparty. He co-ordinates the initiatives in the various parliaments in favor of the establishment of the International Criminal Court on war crimes in former Yugoslavia, and for the international recognition of the Republic of Macedonia.

In 1994 he presents himself as candidate for the European Parliament for the Lista Pannella - Movement of Reformers. In April 1995 the 37th Congress of the Radical Party elects Dupuis as its General Secretary, replacing Mrs Emma Bonino who has become European Commissioner. During the winter of 1995-96 he co-ordinates the organization of the European demonstration "Freedom for Tibet", which demonstration - promoted by the Tibet Support Groups, the Tibetan communities in Europe and the Radical Party -, on March 10, 1996 gathers in Brussels around 6,000 citizens and parliamentarians from all over Europe. In April 1996, following the resignation of Mr Marco Pannella, Dupuis became Member of the European Parliament.