Diatomite is a natural material of sedimentary origin, formed by fragments of diatom skeletons. In this work, we obtained nanoparticles with diameter lower than 450 nm from diatomite frustules. Diatomite nanoparticles, silanized and labeled with rhodamine, have been incubated with cancer cells; internalization has been evaluated by confocal microscopy. The results demonstrate the application of diatomite nanoparticles as drug delivery nanovectors