In the mid-twentieth century, the young priest Jose Mª Arizmendiarrieta created the seed of the cooperatives that gave rise to Grupo Mondragon, where Caja Laboral was created. The aim was for Caja Laboral to contribute "social, economic, and business services" to the industrial cooperatives. It had to obtain funds from the cooperative members to be allocated to their own needs. In addition, in order to organize Social Welfare and Security coverage it launched the Provision Service, laying the foundations for what is now Lagun-Aro.
On 1st February 1960 it opened its first branch, on Ferrerías Street in Mondragon. This branch was followed by others in Aretxabaleta, Elorrio, Placencia, Oñati... with a geographical expansion in which cooperatives emerged.
Around 1962, an Aidit413 was acquired, allowing the progression from hand-written entries to machine accounting. In 1964, the Markina branch was opened, with a female manager, Maite Garcia, which was quite unusual at the time. Caja Laboral started to become the superstructure institution destined to carry out the Group's business, financial, industrial and social coordination. In 1966 the first Mobile Branch was launched, for which a "minibus" was fitted out to visit rural towns and villages.
On 2nd October 1965, a meeting was held at the Spanish Artisan Trade Show, located at 21 Rodriguez Arias Street in Bilbao, with a large group of representatives of agricultural cooperatives from Bizkaia.
On 1st October 1966 it opened its doors to the public for the first time at 8 Alameda de Urquijo Street, in central Bilbao
The joint general management between Beyena, Uteco and Caja Rural was created, forming the much desired single address of the Biscay agricultural cooperative complex. New branches start to open.