Salmonella enterica subspecies enterica serovar Typhimurium, is a leading cause of gastroenteritis food-borne illness that leads to hospitalizations worldwide. These infections are further complicated because of the rapid development of antibiotic resistance and the spread of infections by the resistant strains. Thus, the overall aim of this study is to identify a multidrug-resistant strain of Salmonella Typhimurium, whole genome sequencing, and computational analysis of genome sequence. This study presents a comprehensive analysis of Salmonella Typhimurium ms203, isolated from a gastroenteritis patient in Odisha, India. The strain was characterized by microbiological and biochemical assays using a set of standard tests. An antibiotic-susceptibility test of the strain was carried out using VITEK system. Whole genome sequencing facilitated an in-depth examination of genomic architecture, distribution of pathogenic island regions, and antibiotic-resistant sequences. Utilizing diverse computational tools and bioinformatics analysis, including Prokka annotations, protein-protein interaction analysis, genomic island identification, plasmid and phage characterization, antibiotic resistance gene profiling, and average nucleotide identity (AAI) determination, this study elucidates key insights into the genetic makeup and pathogenic potential of S. Typhimurium ms203. These findings may provide valuable contributions to understanding the epidemiology, pathogenesis, and antibiotic resistance mechanisms of this Salmonella strain, with implications for public health interventions and surveillance strategies.