Seven hundred and forty eight strains of proteus spp were isolated from clinical sources at National Medical Center during recent five years(1968 to 1972). 1. These strains identified as follows: P. mirabilis 357 strains(47.7%) P. vulgaris 140 strains(18.7%) P. morganii 134 strains(17.9%) P. rettgeri 63 strains(8.4%) P. inconstans 54 strains(7.2%) 2. About the incidence between both sexes, male is higher than female. 3. Total numbers of the age group from $20{sim}29$ years, $30{sim}39$ years, and $40{sim}49$ years old respectively are higher than total numbers from other age groups. 4. Seasonal trend shows hot season e.g. August to September is more prevalent. 5. Correlation of strain source with clinical department shows the highest incidence of general surgery next to this, orthopedic surgery, chest surgery, internal medicine, neurosurgery, ENT and pediatrics etc. in descending order. 6. Correlation of strain source with clinical material shows the highest incidence of pus next to this urine, stool, sputum etc. in descending order. 7. The rate of susceptibility to several antibiotics is low in general except gentamicin(82.7%) and carbenicillin(72.9%). However, in case of gentamicin sensitive strains are 15(9.6%) and moderately sensitive strains are 114(73.1%).