The types and severity of invasive pneumococcal disease vary among each transplant population. However, comparative data are lacking. Lung transplant recipients have the highest incidence of bacterial pneumonia among solid organ transplant recipients. Pneumonia secondary to Streptococcus pneumoniae occurs in heart transplant patients at a rate 10 times that found in the general population. It is suggested that besides the intensity of immunosuppression, ongoing immunosuppression is important as a risk factor for invasive pneumococcal disease in transplant recipients.