One of the causes of nosocomial infection is A. baumannii that is a gram-negative coccobacillus bacteria, especially in intensive care units (ICUs). It causes ventilator-associated pneumonia, bacteremia, surgical-site infections, secondary meningitis, and urinary tract infections. [1][2][3] Several factors may contribute to the virulence potential of A. baumannii such as OmpA, Pili, biofilm-associated protein (BAP) and phospholipase D and C. [4][5][6] The recent emergence of MDR A. baumannii has become serious trouble and these MDR strains are quickly distributed among hospitalized patients. Three main mechanisms of antibiotics resistance involve disabling antibiotics with enzymes, decline entrance antibiotics into the target site of bacteria and alteration of the target or cellular functions. 7,8 The World Health Organization (WHO) has published a list of priority pathogens that are resistant to antibiotics for research and development about new antibiotics, including A. baumannii, this shows the importance of antibiotic resistance of this bacterium. 9 Therefore, to investigate the development of antibiotic resistance of this bacterium in Iran, we reviewed articles published in this regard in the years 2012 to 2017. MethodsTo gather the necessary information from published articles from national and international journals, research in various databases was reviewed, including PubMed, Google Scholar, Scopus, SID from 2012 to 2017. Keywords for searching articles, inclusive "antibiotic, drag or antimicrobial resistance" with different combinations of other key text words such as A. baumannii and Iran. After analyzing the related articles, were categorized according to year and antibiotic for a better conclusion. Antibiotics investigated included Aminoglycoside, Fluoroquinolones. ResultsWe reviewed Thirty-six related articles that included 3011 A. baumannii clinical isolates and 25 antibiotics from 2012 to 2017. Antibiotic resistance effect methods in investigated articles include disc diffusion assay (Kirby-Bauer) and molecular method (PCR). The data of antibiotic resistance of 3011 A. baumannii isolates are presented in Table 1. This information demonstrates that the resistance to amikacin, ciprofloxacin, levofloxacin, piperacillin, ticarcillin, ceftazidime, ceftriaxone, cefotaxime, cefepime, trimethoprim/ sulfamethoxazole were high, the resistance to gentamicin, tetracycline, tobramycin, ampicillin/sulbactam, aztreonam, meropenem, imipenem were increased in these years and resistance to polymyxin B & colistin was less or decreased.