The patron saint of Beas de Segura is the Virgen de la Paz. On the eve, a traditional bonfire celebration is held, where the townspeople gather to enjoy themselves, with the typical "cuerva" punch and roast potatoes never missing, before the Virgin is carried in procession through the town's streets on 24 January.

A few days beforehand, the Virgin is moved from the town's sanctuary to the parish church to celebrate her novena and festivities. Much information and many documents relating to the devotion to and patronage of the Santísima Virgen de la Paz as Patroness of this town have been lost over time.

The events begin with the so-called San Marcos Chico, in which small young bulls, without horns or with padded horns, are let out for children to run with. On the 23rd and 24th, the bulls are unloaded from their pens and the brave bulls released, with the day rounded off by a popular open-air dance. On the 25th, the town band plays a wake-up call and parades through the streets to announce that at eight in the morning the bulls will be released into an area closed off by shutting several streets.

After ten in the morning, Mass is held, followed by the procession in honour of San Marcos, in which the saint is accompanied through the town's streets by two decorated young bulls on ropes. After the procession, the bulls are released once more into the enclosed area. The day ends with an open-air dance featuring the various local clubs ("peñas") that take part in the festival. Members of these clubs usually immobilise the bulls in order to fit them with brightly coloured harnesses set with mirrors, an act known as "cascar al toro".

The Brotherhood of San Marcos plays a key role in organising the festival. The origins of the celebration of San Marcos in Beas go back to time immemorial, and as early as the 16th century there is a record that the town of Beas had made a solemn vow to San Marcos, since ancient times, for having delivered them from a plague of locusts. This vow consisted of not eating meat and not slaughtering any livestock on that day, nor opening the butcher's shops.

Since 1993, following heated debate between supporters and opponents of the festival, the roped bull of Beas has been subject to current regulations, under which animals, once run in an enclosed area, must be slaughtered and not returned to their herd. Nevertheless, the custom of the San Marcos bull is so deeply rooted in Beas that a little song is still often sung as an act of reaffirmation and defence of the festival: ¡Viva la fiesta de San Marcos! / Nadie la puede quitar, / ni el alcalde, ni su hermano, / ni Tomás el municipal. ("Long live the feast of San Marcos! No one can take it away, neither the mayor, nor his brother, nor Tomás the town officer.")

In 2000, an application was made for the Feast of San Marcos to be declared of National Tourist Interest of Andalusia, a designation made official in the Resolution of 7 September 2000 issued by the Regional Minister for Tourism and Sports. 

As for the celebration of Holy Week, the passage of time has led to the loss of some traditions, such as making decorative luminarias using eggshells, walnuts and snail shells painted in bright colours, glued with plaster onto a cross when the Good Friday procession of the Santo Entierro passed by, or the custom of blowing long trumpets and horns on that day to summon the faithful to the dawn opening address.

In the early 20th century, there was the curious custom of giving the palm frond that the image of San Juan had carried in the processions to the first unmarried woman who died that year.

The old procession of El Prendimiento has been revived, held on Holy Tuesday, featuring a squadron of Roman soldiers who, after re-enacting the kiss of Judas, arrest and take Jesus prisoner. One of the most striking processions is that of the Cristo de la Veracruz.