A report by the Colorado Department of Public Safety found that between 2012 and 2014 arrests of black adolescents between 10 and 17 years old increased by 58%, while among Latino adolescents arrests were up by 29%.
Meanwhile, among white adolescents the number of arrests fell by 8% overall.
Colorado residents voted to legalise recreational use of marijuana for users over 21 years old in 2012, with the law coming into effect in 2014.
Most juvenile arrests are for possession, for which offenders typically pay a fine.
According to the report, Colorado elementary and secondary schools saw a 34% increase in the number of cannabis arrests between 2012 and 2014.