Grifola frondosa is an edible and medicinal mushroom. The bioaccumulation and potential biovailability of Cu and Zn were studied to obtain mycelium with potential properties as a food dietary supplement. Mycelia grown in the presence of nonmycotoxic concentrations of 100 and 200 ppm of Cu or 25 and 50 ppm of Zn accumulated 200-322 ppm and 267-510 ppm of Cu or Zn, respectively. When these enriched metal mycelia were subjected in vitro to a simulated gastrointestinal digestion, the solubility in these digestive fluids was 642-669 ppm and 102-530 ppm, which represent 32-33% and 0.7-3.5% of the recommended daily intake (RDI) for Cu and Zn, respectively, in 1 g of mycelium. These results are discussed in relation to the RDI values exhibited by two commercial supplements, and arguments are given on the potential use of these mineral-enriched mycelia in capsules (in the case of Cu-enriched mycelia), in food preparations, and also as a component of cosmetic mixtures.