Group B streptococcus (GBS) is the most common pathogen in neonates and may induce the overproduction of cytokines. To further clarify temporal alterations in the levels of various cytokines/chemokines, we measured the concentrations of 16 types of these immunological responders in the serum of a neonate presenting with GBS infection. At birth, the concentrations of different cytokines/chemokines increased and that of granulocyte colony-stimulating factor remained high. Thus, these cytokines/chemokines might be associated with the pathophysiology of GBS infection.