Smith, from Kelowna, B.C., won gold in the 200-metre women's breaststroke in a Pan Am record time of two minutes 24.38 seconds.
Toronto's Martha McCabe finished 0.13 seconds back to take silver. Annie Lazor of the United States finished third in 2:26.23.
Caldwell, from White Rock B.C., set a Pan Am record in the 200 backstroke, winning in 2:08.22.
Dominique Bouchard of North Bay, Ont., was second in 2:09.74, 0.66 seconds ahead of American Clara Smiddy.
Emily Overholt of West Vancouver, B.C., won silver in the women's 200 freestyle, while Edmonton's Richard Funk added silver in the men's 200 breaststroke.
The men's 800-metre freestyle relay team comprised of Victoria's Jeremy Bagshaw and Ryan Cochrane, Stefan Milosevic of Burnaby, B.C., and Alec Page of Cortes Island, B.C., was upgraded to silver from bronze when the United States was disqualified.
The Americans appealed the result. Canada's silver will stand until the appeal is heard on Thursday.