| 2017 | Plenary speaker, Math Congress of the Americas | Montréal |
| 2014 | Yale mathematics morning | Yale |
| 2012 | Synergies And Vistas in Analytic Number Theory | Oxford |
| 2012 | New York Distinguished Lecture | New York |
| 2011 | Lang lecture | Berkeley |
| 2010 | Colloquiua | Princeton U & Institute for Advanced Study |
| 2009 | Kuwait lecture | Cambridge University |
| 2009 | 150 years of the Riemann Hypothesis | Verbania, Italy |
| 2008 | Math Assoc of America Distinguished lecture | Washington D.C |
| 2008 | Plenary speaker, Canada-France joint meeting, II | Montréal |
| 2007 | Erdos memorial lecture | American Mathematical Society |
| 2007 | Journée Arithmétique | Edinburgh |
| 2006 | Jeffrey-Williams lecture, Canadian Math Soc | Toronto |
| 2005 | Gauss-Dirichlet memorial symposium | Gottingen, Germany |
| 2005 | Colloquiua | Stanford & Berkeley |
| 2003 | Plenary speaker, Canadian Math Soc | Vancouver |
| 2002 | Plenary MAA speaker | Annual Joint Meeting, San Diego |
| 1999 | Ribenboim lecture, CNTA | Winnipeg |
| 1996 | Plenary AMS/MAA speaker | Annual Joint Meeting, Orlando |
| 1995 | Journée Arithmétique | Barcelona, Spain |
| 1994 | Invited Speaker, International Congress of Mathematicians | Zurich |
| 1993 | Hundredth Anniversary of Harald Cramer | Stockholm, Sweden |
| 1993 | XXVI National Congress, Soc. Mat. Mexicana | Morelia, Mexico |