After returning from Cuba (1898), Pancho Cossío moves with his family to Renedo (Cantabria) until 1909, when they move to Santander. There, he starts his training, being a disciple of Francisco Rivero, and, in Madrid, of Cecilio Plá (1914). In 1921 Cossío carries out his first exhibition in “El Ateneo” of Santander that repeats next year, where he was called ultraist. At that moment, his work is closed to the aesthetics of works from Barradas, Lagar or the Delaunay. In 1923, he goes, together with the sculptor Daniel Alegre, to Paris where he works in Ucelay´s studio. Shortly afterwards, he meets Picasso, and gets in contact with cubism, surrealism and abstraction. In this period, Pancho Cossío carries out numerous works of still lives, coffee and harbour scenes...with his own style- between surrealism and abstraction - which identify him within the aesthetics of the School of Paris. Right in this period, he collaborates with Spanish magazines as popular as Alfar, Litoral or La Gaceta Literaria.
In 1931 he takes part in a collective show in the Society of Iberian Artists in San Sebastian and carries out an individual one in Le Centaure Gallery of Brussels. Later, he returns to Spain, and collaborates with the Jons´s foundation, joins the Anat. Phalanx and becomes the local chief of Press and Propaganda. During the post-war, Cossío keeps painting portraits, still-lives…in which outstands the final spattering of white particles as in the Portrait of his mother(1942). In the forties and fifties he gets closer again with abstraction, he takes part with the School of Altamira and the Abstract Art Week of Santander(1950).