"Marriage of persons of the same sex is a serious crime against humanity", said the Roman Catholic Archbishop of Yaounde.
"We need to stand up to combat it with all our energy. I am particularly thankful to our local media that has been spreading this message of it as a criminality against mankind."
The remarks follow a three-year jail sentence given earlier this month to 32-year-old Jean-Claude Roger Mbede, who was found guilty of homosexual conduct because he sent a text message to another man which read "I am very much in love with you."
In 2012, at least 12 people were convicted of homosexual conduct in Cameroon. Jail terms have ranged between six months and five years.