Attending and presenting at conferences is a great way to get your work recognized and to build your resume. Here are some great conferences for undergraduate students in computer science, health sciences, math and science fields. And don't miss out on the Carleton University Faculty of Science Research Day each year!

General
National Conferences on Undergraduate Research (in the US - Carleton students can receive funding to attend through the Discovery Centre)
Undergraduate Research Conference 

Biology
Association of Medical Microbiology and Infectious Disease Canada
Canadian Centre for Applied Research in Cancer Control
China-Canada Systems Biology Conference (in Ottawa every other year)
Conference of the Canadian Society of Microbiologists
Science Atlantic Aquaculture & Fisheries and Biology Conference
IEEE Engineering in Medicine and Biology Society (EMBS) International Student Conference (ISC) (at Carleton in May 2016)

Chemistry
Canadian Chemistry Conference and Exhibition
Southern Ontario Undergraduate Student Chemistry Conference 

Computer Science
Canadian Undergraduate Computer Science Conference
Canadian Undergraduate Technology Conference
Grace Hopper Celebration of Women in Computing (in the US)
World Wide Web Conference (in Montreal, Canada in April 2016)

Food Science
Agri-Food Policy Conference 

Earth Science and Geoscience
Advances in Earth Science Research Conference (at Carleton in April 2016)
Alberta Student Energy Conference
Atlantic Universities Geoscience Conference
GeoConvention
Prospectors and Developers Association of Canada (PDAC) Convention 
Western Inter-University Geosciences Conference

Healthcare
Canadian Undergraduate Conference on Healthcare (CUCOH) 
London Health Research Day 

Math
Canadian Undergraduate Mathematics Conference
Statistical Society of Canada

Neuroscience
Brain Health Research Day (at Carleton in June 2016)
Brain Development Conference (was held in Ottawa in September 2015)
Canadian Undergraduate Neuroscience Conference (was offered in 2015, not sure if it will be offered again)

Physics
Canadian Association of Physicists Conference (in Ottawa in June 2016)
Canadian Conference for Undergraduate Women in Physics
Canadian Undergraduate Physics Conference