Las conchas de piangua Anadara spp, recolectadas en un manglar de la Bahia de Buenaventura -Valle - Colombia, se sometierion a digestion en frio con acido clorhidrico analitico (37%) (Tratamiento A) o acido clorhidrico comercial (27%) (Tratamiento B). El rendimiento de carbonato de calcio fue 82.48% y 77.21% respectivamente. La prueba de absorcion atomica arrojo 30.21+ 4% y 27.62+ 0.165% de Ca, sin diferencias significativas (P 20%. ABSTRACT Obtaining Calcium Carbonate from piangua shells. The piangua shells Andara spp, collected in a swamp of the Buenaventura, Valle del Cauca, Colombia, was process for digestion in cold with analytic hydrochloric acid (37%) (Treatment A) or commercial hydrochloric Acid (27%) (Treatment B). The yield of carbonate of calcium was 82.48% and 77.21% respectively. El test of atomic absorption threw 30.21+4% aand 27.62+0.165 of Ca, without significant differences (P 20%. Key words: Anadara spp, Calcium Carbonate, Hydrochloric Acid, Spectrographic analysis, diffraction X ray