| 2017 | Plenary speaker, Math Congress of the Americas | Montréal |
| 2014 | Yale mathematics morning | Yale |
| 2014 | Current Events, Annual Joint Meeting | Baltimore |
| 2012 | Synergies And Vistas in Analytic Number Theory | Oxford |
| 2012 | New York Distinguished Lecture | New York |
| 2012 | Additive Combinatorics | Paris |
| 2012 | AMS special session | Boston |
| 2011 | Wilf 80 | Wilfred Laurier U, Waterloo |
| 2011 | PANTS conference | Emory, Atlanta |
| 2011 | CMS winter meeting | Toronto |
| 2011 | Lang lecture | Berkeley |
| 2010 | MAA meeting | Plattsburgh, NY |
| 2009 | Poetry of Analysis | Madrid |
| 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 | Canadian Number Theory Association | Waterloo |
| 2008 | Plenary speaker, Canada-France joint meeting, II | Montréal |
| 2008 | Algorithmic number theory | Banff |
| 2008 | Additive Combinatorics | Toronto |
| 2008 | Number theory algorithms in Computer Science | Barbados |
| 2007 | Additive Combinatorics | Princeton |
| 2007 | Erdos memorial lecture | American Mathematical Society |
| 2007 | Journée Arithmétique | Edinburgh |
| 2006 | Canadian Number Theory Association IX | Vancouver |
| 2006 | Jeffrey-Williams lecture, Canadian Math Soc | Toronto |
| 2005 | Maine-Quebec Number Theory Conference | Orono, Maine |
| 2005 | Gauss-Dirichlet memorial symposium | Gottingen, Germany |
| 2005 | Conference, Analytic number theory | Quebec |
| 2004 | Maine-Quebec Number Theory Conference | Quebec City |
| 2004 | Canadian Number Theory Association VIII | Toronto |
| 2004 | Moreton lecture | Millsaps College |
| 2004 | Current Events, Annual Joint Meeting | Phoenix, Arizona |
| 2003 | Plenary speaker, Canadian Math Soc | Vancouver |
| 2003 | Colloque des Sciences mathématiques du Quebec | Ottawa |
| 2003 | Hugh Williams' 60th birthday conference | Banff, Alberta |
| 2002 | Canadian Number Theory Association VII | Montreal |
| 2002 | Friends of MSRI | New York |
| 2002 | Plenary MAA speaker | Annual Joint Meeting, San Diego |
| 2001 | Mathematical Association of America | Montgomery, Al |
| 2000 | Millenial Number Theory Conference | Urbana--Champaign, Illinois |
| 2000 | Analytic Number Theory Workshop | IAS Princeton |
| 1999 | Ron Graham Retirement Day | AT & T Labs, New Jersey |
| 1999 | Number Theory Workshop | Leiden, Holland |
| 1998 | Algorithmic Number Theory III | Oregon |
| 1998 | SIDIM Conference | Puerto Rico |
| 1997 | Mathematical Association of America | summer MathFest, Atlanta |
| 1997 | International Number Theory Conference | Penn State |
| 1997 | Analytic Number Theory Workshop | Hong Kong |
| 1996 | Canadian Number Theory Association V | Carleton U, Ottawa |
| 1996 | Plenary AMS/MAA speaker | Annual Joint Meeting, Orlando |
| 1996 | Analytic Number Theory Workshop | Kyoto, Japan |
| 1996 | Combinatorial Number Theory | DIMACS, Rutgers |
| 1995 | Workshop on Organic Mathematics | Vancouver, Canada |
| 1995 | Journée Arithmétique | Barcelona, Spain |
| 1995 | Analytic Number Theory Meeting | Urbana--Champaign, Illinois |
| 1994 | Invited Speaker, International Congress of Mathematicians | Zurich |
| 1994 | AMS Special Session on Number Theory | Oklahoma State |
| 1994 | Canadian Number Theory Association IV | Dalhousie U, Halifax |
| 1994 | Computers in Number Theory | Fields Institute, Ontario, Canada |
| 1994 | Mathematical Association of America | Jefferson City, Tennessee |
| 1993 | Hundredth Anniversary of Harald Cramer | Stockholm, Sweden |
| 1993 | XXVI National Congress, Soc. Mat. Mexicana | Morelia, Mexico |
| 1993 | West Coast Number Theory Conference | Asilomar, California |
| 1993 | Symposium in Experimentation | Western Kentucky University, Bowling Green |
| 1993 | AMS Special Session on Number Theory | Northern Illinois |
| 1993 | L-functional Classical Problems | Isaac Newton Institute, Cambridge, England |
| 1992 | West Coast Number Theory Conference | Corvallis, Oregon |
| 1992 | Mathematical Association of America | Kingston, Ontario |
| 1992 | Number Theory Meeting | Urbana--Champaign, Illinois |
| 1991 | Canadian Number Theory Association III | Kingston, Ontario |
| 1991 | Computational Number Theory and Combinatorial Analysis | Northern Illinois |
| 1990 | Conference on Experimental Mathematics | Dalhousie, Halifax, Nova Scotia |
| 1989 | Combinatorial Number Theory Conference | Lehman College, The Bronx |
| 1989 | Maritime Algebra Day | Sackville, New Brunswick |
| 1989 | Canadian Number Theory Association II | Vancouver |