Background: Ketoconazole was introduced in 1981 as the first in a series of antifungal agents that are characterized by nitrogen-containing ring. Ketoconazole acts against many different kinds of fungi such as candida, dermatophytes and as pergillus. Also oral ketoconazole had proved its effectiveness in the treatment of cutaneous Leishmaniasis. Objective: To evaluate the safety of oral ketoconazole in the treatment of different skin diseases like cutaneous Leishmaniasis (CL), tineacapitis, tineacorporis and tineaversicolor. Patients and Methods: This is a single, blinded, therapeutic, controlled study that was carried out in the Department of Dermatology, Baghdad Teaching Hospital, Baghdad, Iraq, during the time, January 2015 to July 2016. In total, 951 patients with acute cutaneous leishmaniasis, tineacapitis, tineacorporis and tineaversicolor were enrolled in this study. The diagnosis was confirmed by smear and histopathology. Patients were divided into two groups: 51 patients in Group 1; 24 of them were treated with oral ketoconazole tablets 200 mg twice daily for 6 weeks and 27 of them were treated orally with a combination of zinc sulfate 10 mg/kg/day and ketoconazole for 6 weeks. All patients were seen regularly every 2 weeks for 6 weeks of treatment period, then monthly for the next three months as follow up period. Liver enzymes monitoring was done for every patient in this study every two weeks. Elevated liver enzymes were considered as features of hepatotoxicity in the examined patients. While group 2 included 900 patients and was divided into 3 subgroups: A: 600 patients with tineacapitis and tineacorporis, B: 100 patients with tineaversicolor, and C: 200 patients with CL. All patients in group 2 were treated with oral KC tablets 200 mg twice daily for 6 weeks. The dose of oral KC in children is 3.3 - 6.6 mg/Kg/day. All patients in group 2 were not investigated for ketoconazole biochemical side effects but watched for any clinical symptoms and signs of any side effects. Results: After six weeks, 951 patients had completed the treatment. In the first group (51 patients), only two out 27 patients (7.4%) from the combined group showed elevated liver enzymes while the ketoconazole treated group showed no increase in liver enzymes, hence only 3.9% showed elevated liver enzymes that went to normal during follow up. In the second group (900 patients) there were no clinical symptoms and signs in favor of hepatic toxicity or other related organs. Conclusion: Ketoconazole has been used tremendously in treating of different skin diseases including fungal and Leishmania infection but without side effects, accordingly this drug seems safe to be used in treatment of different skin diseases whether adults or children.