Tonsil is not only important for its frequent infection, but also foci of various focal infections such as rheumatism, carditis, glomerulonephritis and so on. The bacterial flora of the palatine tonsillitis has been reported by many investigators since the early twentieth century. But the bacterial flora of the tonsil is continuously changed according to the environmental conditions and by use of many chemotherapeutic agents. The author studied on the recent bacterial flora of chronic tonsillitis, its susceptibility to various chemotherapeutic agents and compared the morphological state of palatine tonsil with its bacterial flora from 50 cases of chronic tonsillitis. The results obtained were as follows : 1) In sex distribution, there were 18 males (18%) and 32 females (64%). The age distribution showed a predilection on adult. 2) The most commonly isolated pathogenic organism was hemolytic Streptococcus(64%). 3) The most common morphological state of tonsil was globular in shape (84%) and Grade II hypertrophy (44%). The isolation rate of hemolytic Streptococcus in Grade II was similar to that of Embedded form. 4) Most of Staphylococcus aureus was isolated from Grade I. 5) In bacteriological susceptibility to the various antibiotics, many strains of Staphylococcus aureus were resistant, and most strains of hemolytic Streptococcus were susceptible.