Although acne vulgaris is common in preadolescents (<13 yrs), few acne treatments are currently approved for children. This study assessed the safety and efficacy of tretinoin microsphere gel (TMG) 0.04% pump in children aged 9-11 with acne vulgaris. In this multicenter, randomized, double-blind, vehicle-controlled pilot study, patients applied TMG 0.04% pump or vehicle once daily to the face for 12 weeks. Efficacy measures were changes in facial lesion counts, Investigator Global Evaluation of acne severity using two scales, and Investigator Global Assessment of Improvement from baseline to week 12. Of the 110 patients enrolled, 55 received TMG 0.04% pump, and 55 received vehicle. At week 12, there was significantly greater improvement in the least-squares mean change in noninflammatory lesions with TMG 0.04% than with vehicle (-19.9 vs -9.7, p = 0.04) and a significant difference in Investigator Global Assessment of improvement at week 12 between the children treated with TMG 0.04% pump and those treated with vehicle (p = 0.02), but there were no discernible differences in static acne severity scales. Change from baseline in signs and symptoms of cutaneous irritation were similar between the active and vehicle arms at week 12. This study demonstrated statistically significant differences in the reduction of noninflammatory lesions between TMG 0.04% pump and vehicle in patients aged 9-11 with acne vulgaris. Additional studies are warranted to further characterize the safety and efficacy of TMG 0.04% pump for the treatment of acne in the preadolescent population.