Background: 5-fluorouracil (5-FU) has proven to be an effective therapy in the treatment of a variety of dermatologic conditions. Approved by the United States Food and Drug Administration for the treatment of actinic keratoses and superficial basal cell carcinoma, topical 5-FU has also demonstrated efficacy in the treatment of a variety of other dermatologic diseases. Methods: A search of the MEDLINE standard computer database, MEDLINE advanced database, and EMBASE database was conducted. Results: Thirty-four articles met criteria for inclusion in this review. These articles represented 16 randomized controlled trials and 18 case series. Each article was reviewed and summarized. Conclusions: Topical 5-FU is used in a variety of dermatologic disease processes with a wide range of efficacy and levels of evidence. Based on extent and level of evidence, our disease-specific systematic review found that the evidence is strongest for topical 5-FU use in the treatment of actinic keratosis, squamous cell carcinoma, and basal cell carcinoma. This review serves as a comprehensive summary of topical 5-FU use in dermatology.