Among couples who were still married during the survey, those who met online reported higher marital satisfaction -- an average score of 5.64 on a satisfaction survey -- than those who met offline and averaged 5.48.
The lowest satisfaction rates were reported by people who met through family, work, bars/clubs or blind dates.
"These data suggest that the Internet may be altering the dynamics and outcomes of marriage itself," said Cacioppo.
Eli Finkel, a professor of social psychology at Northwestern University, led an extensive review of the science published about online dating last year.
He told AFP he agreed with the proportions found in the PNAS study.
His research showed about 35 percent of relationships now start online.
"We found evidence for a dramatic shift since the advent of the Internet in how people are meeting their spouse," said the study, led by John Cacioppo of the University of Chicago's Department of Psychology.
marriages begin with online dating, and those couples may be slightly happier than couples who meet through other means, a U. The research is based on a nationally representative survey of 19,131 people who married between 20.
Online dating has ballooned into a billion-dollar industry and the Internet "may be altering the dynamics and outcome of marriage itself," said the study by U. researchers in the Proceedings of the National Academy of Sciences.
However, some experts took issue with the findings because the survey was commissioned by e Harmony.com, the dating site that attracted one quarter of all online marriages according to the research.
Cacioppo acknowledged being a "paid scientific advisor" for the website, but said the researchers followed procedures provided by the Journal of the American Medical Association and agreed to oversight by independent statisticians.
People who reported meeting their spouse online tended to be age 30-49 and of higher income brackets than those who met their spouses offline, the survey found.