Acinetobacter baumannii is a known hospital aquired pathogenic bacterium that increasingly resists antibiotics treatment. In order to characterize and produce a soluble OmpA protein that can be used to develop Acinetobacter vaccine, polymerase chain reaction (PCR) was used to produce the ompA gene, of A. baumannii strain LI311, which was cloned into the histidin taged pET19b expression plasmid. Immobilized metal affinity chromatography (IMAC) was utilized to purify the recombinant protein, and amino acid sequences for OmpA protein homologs were attained from the National Center for Biotechnology Information (NCBI) protein resource then analyzed using the blast tool and Jalview program. Protein topology prediction was done using NCBI tools and PRED-TMBB2. Analysis of amino acid sequence of OmpA of A. baumannii strain LI311 showed that it has homologies to other clinical Acinetobacter spices , including: A. pittii , A.nosocomialis , A.seifertii, A. calcoaceticus, and A. ursingii with identity percentages of 100%, 100%, 96%, 92%, and 91%. Protein topology prediction revealed two conserved domains belonging to OmpA family protein ,which are beta-barrel domain outer membrane protein (OMP_b-brl) and OmpA-C-like domain, and it is a 10-βeta -stranded transmembrane Outer Membrane Protein with a signal peptide at residues 1–22A. A recombinant Histidine tagged- OmpA (39.31kDa )was successfully expressed and purified in this study. In conclusion, OmpA protein of A.baumannii strain LI31 is highly conserved across clinical species of Acinetobacter, and the soluble recombinant OmpA created in this study can be used to develop a putative vaccine that may prevent infections caused by the clinical species of Acinetobacter.