Clindamycin and lincomycin have a similar mode of antibacterial action, similar antibacterial spectra and they are used frequently in clinical practice. Irrespective of their anti-microbial properties they are suggested to modulate immune function. The aim of our study was to estimate the effect of these antibiotics on neovascular reaction induced in mice skin by mononuclear cells (MNC) collected from the blood of 8 healthy volunteers. Mononuclear cells were injected intradermally into anaesthetized Balb/c inbred mice. Clindamycin, lincomycin or PBS (control) were administered subcutaneously into the mice over 3 days at doses of 3, 15 and 75 mg/kg of the body mass. The number of newly formed blood vessels was counted in dissection microscope 72 h after cells injection. Lincomycin did not change the results of angiogenesis tests comparing to the control . On the contrary, clindamycin administration resulted in strong stimulation of angiogenic response at all used doses. Monocytes and CD8+ cells inhibited angiostimulatory effect of clindamycin administration.