Diverse Streptococcus species including Streptococcus Pneumoniae, Sanguis, Gordonii, Mitis and Mutans cause life-threatening conditions including pneumonia, bacteremia and meningitis. These diseases bear a high morbidity and mortality and for this reason, understanding the key events in the pathogenesis of these infections have a great significance in their prevention and/or treatment. Here, we describe as how the activation of the platelets and their affinity to bind to bacterial proteins act as early key events in the pathogenesis of Streptococcal infections.