Just 45% over the over 20,000 weddings in Ireland last year were in Catholic churches, new data from the CSO reveals.
The data also shows that Irish brides and grooms are getting older and summer dates are the most popular for weddings.
As the number of weddings in Catholic churches dropped from over 49% in 2018, the number of couples choosing Humanist and Spiritualist Union of Ireland ceremonies is also on the rise.
A Humanist ceremony was the choice of 1,813 opposite-sex couples and 100 same-sex couples in 2019, while 1,512 opposite-sex couples and 106 same-sex couples opted for a Spiritualist Union of Ireland ceremony, the CSO data reveals.
Civil marriage ceremonies accounted for almost two-thirds (62.2%) of same-sex marriages, while almost a third (30.6%) of opposite-sex couples chose a civil marriage ceremony.
There were a total of 640 same-sex marriages last year, a slight decrease on the 2018 figure.
The average age of a man getting married in Ireland last year was 36.8, while the average age for women was 34.8.
Despite the drop in popularity, a Catholic church wedding is still the most popular choice for couples.
There were 8,863 couples married in churches last year.
The CSO say they expect a drop in the number of weddings in 2020 due to the outbreak of the coronavirus.