<p>The present study was focused on determining the synergy between a bacteriophage isolated from sewage and the antibiotic ampicillin against <i>Staphylococcus aureus</i>. The isolated phage exhibited a contractile tail and an icosahedral head and was placed in the class Caudoviricetes. Thermal stability of the phage at physiologically relevant temperature 37&#xa0;°C was established by a statistically non-significant (<i>p</i> &gt; 0.05) reduction of 0.158822-log in the plaque count of the phage kept for 24&#xa0;h. In phage-antibiotic synergy experiments, treatment with phage (10⁵ plaque forming units) along with a sublethal dose of ampicillin produced a significantly (<i>p</i> &lt; 0.05) higher reduction in bacterial count as compared to phage or antibiotic used alone. When compared to untreated control, phage-antibiotic combination decreased (<i>p</i> &lt; 0.05) the bacterial count by 2.1522-log, however when phage and antibiotic were used separately, the reductions were 0.8983-log and 0.4503-log, respectively. Additionally, a two-fold reduction (from 8&#xa0;µg/mL to 4&#xa0;µg/mL) in the minimum inhibitory concentration of ampicillin against <i>S. aureus</i> was observed when it was used in combination with phage. These observations revealed a synergistic relationship between the isolated phage and ampicillin against <i>S. aureus</i> and suggest that the addition of phage can prove to be a solution for increasing the efficacy of the antibiotic against resistant bacterial strains.</p>