In this work, a new type of particles denoted as MOFs or Metal-Organic Frameworks, have been studied as a new drug carriers. First, they were synthesised at the nanoscale (NPs) using, when possible, biofriendly methods. Their cytotoxicity, as well as that from their constitutive linkers, was evaluated by the MTT test in murine macrophage (J774) and in cervix carcinoma (HeLa) cell lines, observing: (i) a low cytotoxicity of MOFs, comparable with other described particulated systems, (ii) a strong influence of the composition (toxicity order: Fe