For use in medical and life science research, a device and sample preparation methods were developed to irradiate cultured cells and individual animals with a focused microbeam of cyclotron-accelerated heavy-ions. The new irradiation device positions both sample and microscope with micrometer precision. The beam size is smaller than 3 μm when the distance between the beam exit from vacuum to the irradiation device is less than 500 μm for 13.0 MeV/n 20Ne ions. This beam size is sufficiently small to irradiate intracellular targets in cultured cells. A beam size smaller than 10 μm was obtained for 12C ions of 26.7 MeV/n at a distance of 2 mm from the beam exit, which enabled irradiation of specific cells in a small model animal. Methods to prepare cultured cells and the nematode Caenorhabditis elegans for irradiation using the new device are reported, and the results of the first irradiation experiments presented