The in vitro activity of griseofulvin and ketoconazole was investigated against Trichophyton mentagrophytes (Robin) Blanchard and T. Simii (Pinoy) Stockdale, Mackenzie and Austwick. A gradual decrease in growth was observed with increase in concentration of both antibiotics. Ketoconazole was the more effective antibiotic than griseofulvin as it observed to inhibit > 50% mycelial weight even at a lower concentration of 100 ppm. While griseofulvin was effective to cause > 50% growth inhibition only at higher dosage of 400 ppm.