A bacteriological study of 50 appendectomy cases for patients diagnosed by physicians to be appendicitis, within Kirkuk province was carried out to isolate the habitat bacteria of appendix and to assess the impact of some antibiotics on isolated bacterial species from the appendices. The age of patients ranged between 3 -45 year old (21 male and 29 female). The culture results showed 94% single isolate with 2% negative growth and 4% mixed growth were obtained. The gram positive bacteria isolate formed (11.77%) less than gram negative (88.23%). The total isolates represented 51 included Escherichia coli 34 (66.66%), followed by Enterococcus faecalis 3 (5.89%), Klebsiella pneumonia 3 (5.89%), Citrobacter youngae 2 (3.92%), Raultella terrigena 2 (3.92%), Pseudomonas aeruginosa 2 (3.92%), Enterrobacter cloacae 1 (1.96%), Serratia fonticola 1 (1.96%), Entercoccus faecium 1 (1.92%), Staphylococcus epidermides 1 (1.96%) and Staphylococcus xylosus 1 (1.96%). The Staphylococcus xylosus was the first time to be isolated in Kirkuk city while both of Raultella terrigena and Citrobacter youngae were isolated for the first time in appendix samples. Only 16 various antibiotics were tested against Enterobacteriaceae and Pseudomonas aeruginosa while 12 and 7 against Staphylococcus sp. and Enterococcus sp., respectively. The Imipenem and Amikacin were found to be most effective antibiotics against all Enterobacteriaceae isolates and Pseudomonas aeruginosa while Ampicillin, Piperacillin, Ceftazidime, Augmentin, and Cephalothin were ineffective against all isolated bacteria. The Penicillin and Vancomycin were effective against gram positive bacteria.