Potentially malignant oral disorders are all conditions that can precede the development of oral cancer. The traditional World Health Organization 1978 division into premalignant lesions and premalignant conditions was abandoned in 2005 when the WHO proposed the use of the term potentially malignant oral disorders (PMOD). The use of the terminology like "precancer", "epithelial precursor lesions", "premalignant", "precancerous" and "intraepithelial lesions" is not recommended in the scientific literature. The definition of oral disorders was updated in 2020 at the WHO consensus workshop to "any abnormal change in the mucosa in the oral cavity associated with a statistically increased risk of developing oral cancer". PMOD includes leukoplakia, proliferative verrucous leukoplakia, erythroplakia, oral submucosal fibrosis, oral lichen planus, oral lichenoid lesions, actinic cheilitis (actinic keratosis), palatal lesions in reverse smokers, discoid lupus erythematosus, oral graft-versus-recipient reaction, and hereditary disorders and immunodeficiencies. The most common PMOD are leukoplakia and erythroplakia. The most common etiological factors are the consumption of alcohol and tobacco products and their synergistic effect. The diagnosis of PMOD is often a special challenge, and is based on taking a detailed dental and medical history, on clinical findings, biopsy and auxiliary diagnostic methods. Biopsy is the method of choice in the diagnosis of PMOD. The treatment includes a conservative and surgical approach, and the prognosis itself depends on early diagnosis. A conservative approach implies monitoring the disease and, most often, prescription medication treatment, which can be topical and systemic, while the surgical approach consists of the usual surgical excision, cryotherapy, electrocoagulation and laser ablation, most often with a CO2 laser. Regular monitoring of the patient after therapy is extremely important.