The world experience of composing music for films spans over a century, encompassing the creation of scores for films of various genres. Over the course of its existence, film music has solidified its position as an integral part of this form of art. Similar to any specific genre, film music has developed its own set of laws: the power of impact, stylistics, form development, musical language, dramaturgy, instrumentation, principles of functioning, methods of integration with other components of the film, etc.The comprehensive focus on the research subject necessitates the application of a systematic approach, employing multi-disciplinary methods. Historical-art, culturological and analytical methods, which are fundamental in the article, allow to achieve the intended aim. Due to an interdisciplinary approach, the theoretical foundation of the article is based on the works of philosophers, culturologists, art historians, film experts and musicologists, aiming for the most comprehensive exploration of the issue.Film music, serving as a colossal in volume and still insufficiently explored artistic domain, holds particular interest for musicology. It is characterized by a significant array of questions, encompassing both scientific-theoretical and practical issues. The scope of this article includes issues of theoretical principles of film music, including genre and artistic-stylistic features, methods of interaction with visual elements, questions of authorship, instrumentation, the relationship between sound and visual components, problems of form, functioning, etc. Having considered the theoretical aspects of the research subject, it becomes evident that music and sound have become one of the most crucial components of synthetic screen art. The musical structure of a cinematic work presents its multifaceted characteristics, contributing to the fullest realization of the creators’ intentions. The work defines the main terminological categories of the «film music» phenomenon, analyzes the existing systems of foreign researchers regarding the classification of functions, gives a genre description of music in the main types of films and also presents a generalized and expanded classification of the functions according to the criterion of dramatic role.