The Manchester City manager made the sizeable contribution to the Angel Soler Daniel Foundation, which will invest it in medical equipment.
Guardiola is at home in Barcelona amid the COVID-19 outbreak and the foundation to which he made the pledge is focused on tackling the virus in the region.
The organisation's fundraising efforts started on March 21 and prior to Guardiola's gesture had raised €33,000.
A statement read: "Former football player and former FC Barcelona coach and current Manchester City manager Pep Guardiola has made a donation of one million euros to the Angel Soler Daniel Foundation for the purchase and supply of medical equipment in the face of a health emergency of the COVID-19 pandemic.
"The donation campaign promoted by the Colegio de Doctors de Barcelona and managed through the Angel Soler Daniel Foundation aims to collect medical material and financial contributions from collegiate doctors and the general population for the purchase of medical equipment and equipment that is currently lacking in health centers in Catalonia.
"Also to be able to finance the alternative production (through 3D printing and others) of respirators and other elements of protection for healthcare staff."