Bacteriophage phiKZ was investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The well-known phage T4 was used as a reference sample. Reproducible contact mode AFM images of native and partially disintegrated particles of bacteriophage phiKZ in air were obtained. It was demonstrated that the heads of phiKZ and T4 phages were compressed differently and depended on adsorption onto highly ordered pyrolytic graphite and mica. We have established a procedure to partially disintegrate the viral particles after which the internal protein body, which is a helical structure with a cylinder-like form, was easily observable inside the bacteriophage phiKZ head.