The objective of this study was to determine the incidence of bovine mastitis caused by Staphylococcus aureus and to evaluate antibiotic resistant pattern among isolated S. aureus causing bovine mastitis. A total of 400 cattle milk samples from 3 dairy farms of district Khairpur located in Thehri, Gambat and Khairpur were collected in sterilized bottles. Clinical mastitis was noted based on signs of inflammation in the udder and obvious changes in milk. Subclinical mastitis was evaluated using the California mastitis test (CMT). Bacteria were isolated and identified from milk samples based on cultural, microscopic and biochemical tests. The isolated strains were then tested for their antibiotic sensitivity profile by Kiry-Baur disc diffusion assay. Out of 400 milk samples tested, 255 samples (63.55%) were positive for mastitis as indicated by CMT. S. aureus was isolated from 109 samples (26.25%) as confirmed by yellow colored colonies on Mannitol salt agar, Gram positive cocci in bunches and positive for catalase, coagulase, DNase and beta hemolysis.  Area wise prevalence of S. aureus was noted as 31.34%, 28.57% and 21.8% in Khairpur, Thehri and Gambat respectively. S. aureus strains were highly resistant to the antibiotic Meropenem (81.6%) followed by Cefixime (61.4%) Cefotaxime (60.55%), Oxycillin (55%), Erythromycin (54%), Ampicillin (51.3%), Ciprofloxacin (38%), Cefradine (37.6%), Sulphametho-Trim (21.1%), Vancomycin (21.1%), Doxycycline (21.1%) and Amoxicillin-clavulanate (5.5%). This study suggests that clinical and subclinical form of S. aureus associated mastitis is highly prevalent among dairy cattle of district Khairpur and S. aureus has become resistant to most of the antibiotics. Hygiene status of animal is very much essential to control mastitis and to prevent the spread of resistant bacteria to other animals.