C. pneumoniae has the capacity to inhibit apoptosis. Here we provide further insight into how infection with C. pneumoniae affects the apoptotic signal transduction in infected human epitheloid cells. For assessing changes in the apoptotic response, intact cells and cell extracts were used. These results show that C. pneumoniae is able to interfere with the host cell's apoptotic apparatus at least at two steps in the signal transduction.