Nowadays, patients are becoming increasingly interested in cosmetic dentistry. There is an increasing interest from patients in having white nice teeth. Teeth whitening is among the most popular cosmetic dentistry procedures. The procedure is well researched and scientifically proven and therefore safe for the patient. There are external and internal teeth whitening. Materials used include hydrogen and carbamide peroxide as well as sodium perborate, which release active oxygen in the process of oxidation. Not every patient is a candidate for teeth whitening and a full dental examination is mandatory to assess things that can have an impact on the success of whitening. In accordance with the EU Directive (2011/84/EU), cosmetic products are those products containing more than 0.1% and up to 6% of hydrogen peroxide release and may be used only by dentists, or by patients under their direct supervision for aesthetic purposes. Products containing more than 6% of hydrogen peroxide are classified as medical products. Whitening can have adverse effects on oral hard and soft tissues. One of the most important adverse effects is root resorption which may result in tooth loss. There are several teeth whitening techniques. Internal (non-vital) whitening techniques include laser, thermocatalytic and "walking bleach" techniques, performed in-office under the supervision of a dentist. External whitening techniques include enamel microabrasion, "power bleach" and whitening using a whitening tray at home. Best results are produced by combining in-office whitening using a Zoom lamp, and at-home methods for additional two weeks. The patient becomes more motivated, and the procedure results in outstanding long-term outcomes.