The Iowa State University study found that kids who exceed the recommended two hours of daily screen time per day are almost twice as likely to have attention problems.
Both the American Academy of Pediatrics and the Canadian Pediatric Society recommend parents limit a child's screen time to one or two hours daily.
But co-author Douglas Gentile says the average child in the U.S., and likely in Canada, spends many more hours per day with screen-based technology.
The researchers analyzed screen time and attention problems for both elementary school kids and college students in their 13-month study.
Gentile says attention problems in the classroom got worse in relation to how much time kids spent in front of the TV or playing video games.
The study is published in the July issue of the journal Pediatrics.