Recently, it has been recognized, that oral infection especially periodontitis may affect the pathomechanism and course of a number of systemic diseases, such as: cardiovascular, cerebrovascular diseases, atheromatous peripheral vascular disease bacterial pneumonia, diabetes mellitus, osteoporosis, or cause adverse pregnancy outcome. This review will focus on the current knowledge linking periodontal infections to a set of above mentioned systemic diseases. While a number of their mutual interactions have been already identified, additional research will be required to determine with certainty, whether these associations are casual or coincidental and to evaluate disease pathogenesis and potential therapeutic interventions.