Fluoride varnishes were developed as alternatives to the conventional topical applications, mainly to prolong contact time between fluoride and teeth. Two marketed products, Duraphat and Fluor Protector, have been extensively tested and are generally accepted for clinical use. In this overview of fluoride varnishes the state of the art of both products is presented. Fluoride uptake, demineralization inhibition and caries prevention induced by varnish applications are discussed. In general it is concluded that varnishes are toxicologically safe, easy to use, and possess excellent cariostatic properties. When re-applied regularly, twice a year, and combined with normal oral hygiene procedures they are topical fluoride agents with very good caries preventive properties.