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. 

A festival experienced with great emotion and tradition in our town, the Fiestas del Toro Ensogado, in Honour of San Marcos, are held from 22 to 25 April. During these days, the bull, symbol of the Evangelist Saint, holds a prominent place in the proceedings as the festival's key totemic animal, with young men, in their confrontation with the fierceness of what represents an inescapable challenge from nature, trying to master it and make it docile before the image of San Marcos.

These festivities are preceded by the traditional pilgrimage in Honour of San Marcos, organised by the Brotherhood of San Marcos and held on the first Sunday of April. The image of the Saint sets off in procession from the square of the same name towards the Cortijo de "El Álamo". Along the way, which passes through our green olive groves, a Mass is held. In the early afternoon, prizes are awarded in various categories: best rope-handler, best evasive move, and best harness. The Sanmarquera Queen and her first lady-in-waiting are also named.

The start of the San Marcos festivities is marked by the opening address, delivered from the balcony of the Brotherhood of San Marcos headquarters, attended by large numbers of residents and visitors. It marks the official start of the celebrations.

If the word "Hermandad" (Brotherhood), as coordinator of this extensive festival, means fraternity and affection, the "Peñas" (local clubs) carry on this friendship, keeping their doors open to all who visit us during these days. After their intense work throughout the year, during these days each of them becomes a true ambassador for Arroyo del Ojanco, for the hospitality and friendliness of its people. The Peñas bring joy and warmth to San Marcos.