The main advantage of PDT in laryngology seems to be its non-invasiveness and the possibility of using it despite of previous application of conventional methods. In the study application of PDT in two separated groups of patients, i.e. 8 patients previously treated by surgery and radiotherapy with local recurrence (SCC) or with advanced primary lesion and 12 patients with oral leucoplakia. In the first group delta-aminolevulenic acid (ALA) was administered orally, while in second one an ointment containing 10% ALA was applied locally. In the both groups prior to irradiation the tissue level of protoporphyrin IX was verified by adapted Xillix LIFE machine. All treated lesions were irradiated with argon-pumped dye laser. In leucoplakia group complete response was achieved in 10 out of 12 treated patients. In group of advanced cancers the only partial response was obtained--the diminution of cancer ulceration was observed. On the basis of our preliminary results the usefulness of PDT may be suggested in eradication of premalignant lesions of oral cavity and palliation of advanced cancers within pharynx and larynx.