Seborrheic dermatitis traditionally has been treated with topical steroids. In current practice, however, antifungal agents such as ketoconazole often are used because Malassezia yeasts are thought to play a role in the disease pathogenesis. Ketoconazole gel 2% has been developed for the once-daily treatment of seborrheic dermatitis. This gel is almost invisible after application, unlike ketoconazole cream, and may offer advantages in patient acceptance and adherence to treatment. Three randomized, double-blinded, vehicle-controlled, multicenter, parallel-group phase 3 studies evaluated the efficacy and tolerability of ketoconazole gel 2% compared with a vehicle gel in more than 900 subjects with moderate to severe seborrheic dermatitis who applied treatment for 14 days and were followed for an additional 14 days. Two of these studies also compared a combination gel containing ketoconazole 2% and desonide 0.05%, each active gel individually, and a vehicle control. Subjects were considered effectively treated if the erythema and scaling as well as investigator global assessment (IGA) scores decreased to 0 (or 1 if the baseline score was ≥3) by day 28. Pooled data from these studies showed that the proportion of effectively treated subjects was significantly greater in the ketoconazole gel 2% treatment group compared with the vehicle group (P<001). The comparison of the combination gel to its individual components revealed that the efficacy of ketoconazole alone was comparable to the combination gel as well as desonide gel alone for up to 2 weeks after the end of treatment. These data suggest that once-daily ketoconazole gel 2% is an effective treatment for seborrheic dermatitis and a viable alternative to the ketoconazole cream 2% formulation.