There is a widespread perception among Spanish pediatricians that the incidence of empyema has significantly increased in the last few years, even though the objective information available is limited, and there is no specific active epidemiological surveillance system for this condition. In the present article, we review the situation of empyema in Spain, and discuss the main hypotheses put forward in the international literature to explain this increase, as well as the limitations of the sources available. Despite the scarcity of information, we draw the following conclusions: 1) the incidence of pediatric empyema is increasing in Spain, both generally and when caused by pneumococcus in particular; 2) the reason for this increase remains unknown, and to date no firm link has been established between this phenomenon and the heptavalent conjugate pneumococcal vaccine; and 3) this situation justifies the establishment of prospective systems for the surveillance and control of empyema and, once again, highlights the importance of developing active surveillance systems for pneumococcal disease.