The nanoscale version of diamond results to be very useful as functionalized material for medical devices such as coating layers for prosthesis, drug delivery, and implanted sensors. For this reason, the diamond nanoparticles (DNPs) should not be against the cells’ viability, when the patients are treated with ionizing radiation. To study the cells’ response after a radiation treatment in the presence of DNPs it was considered to use yeast cells, were considered because of their simplicity, and they are suitable as eukaryotic cells. The aim of this work is to study the influence of DNPs radiated with electron beam radiation treatment and on the viability of the yeast cells being the organism model. DNPs were radiated with a dose rate of 1 to 6 Gy/min, the dose from 15 to 30 Gy, and energy from 6 to 20 MeV, with irradiated DNPs mixed with yeast cells, increasing viability of the cells four times; on the other hand, considering this mixture of DNPs and yeast cells allow to understand if the yeast cells’ viability could be influenced by the ionization treatment with the presence of DNPs in solution. The post-treatment of the DNPs and yeast cells solution ended up with a decrease of the yeast cells’ viability of 20%. With this study it has been proved that some cells could survive and remain unaltered after a radiation treatment, with instead a viability enhancement, highlighting potential safety and health issues if considering more dangerous cells.