Inhibitive and adsorption characteristics of ampiclox, ampicillin, cloxacillin, chloramphenicle and tetracycline on the corrosion of mild steel have been studied using weight loss, gasometric and thermometric methods. The results obtained reveal that various concentrations of ampiclox, ampicillin, cloxacillin, chloramphenicle and tetracycline inhibited the corrosion of mild steel in H2SO4 between the temperature range of 303 – 333K. Values of inhibition efficiencies of these inhibitors (at 303K) were relatively high and ranged from 88.78 to 94.63%, 78.15 to 89.96%, 90.40 to 93.98%, 8.75 to 34.33% and from 85.78 to 95.52% for ampiclox, ampicillin, cloxacillin, chloramphenicle and tetracycline respectively. Chloramphenicle did not inhibit mild steel corrosion at 303K. The inhibition efficiency of these inhibitors was found to decrease with temperature. Due to synergism, the inhibition efficiencies of these inhibitors were further enhanced. Correlation between inhibition efficiencies of the studied compounds and quantum chemical parameters were excellent. Excellent correlation was also observed between theoretical (obtain through QSAR) and experimental inhibition efficiencies.