Prince Jacques is next in line to the Monaco throne, a rich principality on the southern French coast.
A statement said both babies were doing well. Gabriella was born first, with Jacques arriving two minutes later.
Their father is Prince Albert II, 56, son of the late Hollywood actress, Grace Kelly. Charlene, 36, is a Zimbabwean-born former Olympic swimmer.
The couple married in 2011.
The prince has two other children but they are excluded from the throne because they were born outside of marriage.
Ahead of the birth, Prince Albert said that the first child to be delivered would become next-in-line, if the twins were the same sex.
But since the twins are mixed sex, Jacques takes the role, due to Monaco's laws of succession favouring males.
The gender of the twins had been kept a secret even from their father during Charlene's pregnancy.
Forty-two canon shots were fired to mark the babies' arrival, 21 for each infant.
It is the first time twins have been born to Monaco's royal family since it was founded in the 13th Century.
Monaco's Princess Charlene has given birth to twin babies, Gabriella and Jacques, the palace has announced.