If you want a full list you have to take some extra information along with it. If you just type 'world leaders list' in a search engine, for instance, you can get the information in different ways - either a list of leaders past and present, or of leaders plus their top government officials. If you clickhere you can see an example.
Ahmadinejad, Mahmoud Bachelet Jeria, Verónica Michelle
Basescu, Traian Berger Perdomo, Óscar José Rafael
Brown, James Gordon Calderón Hinojosa, Felipe de Jesús
Castro Ruz, Raúl Modesto Cavaco Silva, Aníbal Antonio
Chávez Frías, Hugo Rafael Couchepin, Pascal
Duarte Frutos, Óscar Nicanor Fernández de Kirchner, Cristina
Fischer, Heinz Harper, Stephen Joseph
Jintao, Hu Kaczynski, Lech Aleksander
Key, John Phillip Köhler, Horst
Ludwig García Pérez, Alan Gabriel Lula da Silva, Luiz Inácio
McAleese, Mary Patricia Medvedev, Dmitry
Morales Ayma, Juan Evo Mubarak, Muhammad Hosni Said
Napolitano, Giorgio Obama, Barack Hussein
Olmert, Ehud Ortega Saavedra, José Daniel
Patil, Pratibha Reinfeldt, John Fredrik
Rodriguez Zapatero, José Luis Rudd, Kevin Michael
Sarkozy, Nicolas Uribe Vélez, Álvaro
Vázquez Rosas, Tabaré Ramón Yudhoyono, Susilo Bamb
Basescu, Traian Berger Perdomo, Óscar José Rafael
Brown, James Gordon Calderón Hinojosa, Felipe de Jesús
Castro Ruz, Raúl Modesto Cavaco Silva, Aníbal Antonio
Chávez Frías, Hugo Rafael Couchepin, Pascal
Duarte Frutos, Óscar Nicanor Fernández de Kirchner, Cristina
Fischer, Heinz Harper, Stephen Joseph
Jintao, Hu Kaczynski, Lech Aleksander
Key, John Phillip Köhler, Horst
Ludwig García Pérez, Alan Gabriel Lula da Silva, Luiz Inácio
McAleese, Mary Patricia Medvedev, Dmitry
Morales Ayma, Juan Evo Mubarak, Muhammad Hosni Said
Napolitano, Giorgio Obama, Barack Hussein
Olmert, Ehud Ortega Saavedra, José Daniel
Patil, Pratibha Reinfeldt, John Fredrik
Rodriguez Zapatero, José Luis Rudd, Kevin Michael
Sarkozy, Nicolas Uribe Vélez, Álvaro
Vázquez Rosas, Tabaré Ramón Yudhoyono, Susilo Bamb