The Santa Maria church is one of the most significant works of neoclassical architecture in Bizkaia. The neoclassical portico (porch area just outside of the church for congregating before and after services, traditional of Basque churches), part of the main façade, draws attention with it’s Doric columns that support a triangular pediment.

The church has a ground floor built in the shape of a cross, a semicircular apse and two towers that are connected to the main façade. The central part of the church is covered with a large 8 piece cupola. The rest is covered with smaller cupolas with the exception of the apse and the lateral chapels that are corner pieces.

On the inside, the altarpieces are of high quality. The sculpture of the Assumption of Mary is Romanist and probable reused from the old church of Atalaya, a work by Martín Basabe.

The construction of the church was ordered in 1783 by Colón de Larreategi, but the construction did not commence until 1823. The blueprints done by the architect Silvestre Pérez were followed and the church was inaugurated in 1858.

Every August in Bermeo there is a week dedicated to international music and it is celebrated in this church, making use of the breathtaking organ and the acoustics of the grand cupola.