In the field of laryngology, the importance of mass communication and the evolution of surgical procedures for improvement of voice have created new interest in improvement of function studies for accurate diagnosis of laryngeal diseases and voice disorders. Diagnostic evaluation for laryngeal diseases and voice disorders require a multidimensional approach such as physiological examination of the larynx and vocal tract, aerodynamic studies, examination of vocal fold vibrations, neuromuscular studies, acoustical analysis and psychoacoustic evaluation. The aerodynamic investigations of the vocal tract present valuable information about the efficiency of the larynx in translating air pressure to acoustic signal. Several acoustic tests afford an accurate assessment of the acoustical parameters for differentiating pathological voice from the normal. The utilization of electromyography for evaluation of the different laryngeal muscles is available for diagnosis of various laryngeal disease. The psychoacoustic evaluation of the voice is also useful for evaluation of the voice disorders. This multidimensional approach permits a comprehensive image of the vocal function for diagnostic and prognostic studies, medicolegal evaluations and therapeutic determinations. The medical application of these scientific measurements offers the development of research in laryngology and phoniatrics.