The subject matter of this article focuses on questions relating to the application of categories of 'musicality' to paintings. These issues go beyond questions of musical iconography, being concerned with the search for qualities perceived as 'musical' in the actual formal structure of a painted work of art. Attempts at achieving 'musical' quality in a painting may be the result of conscious moves taken by the artist, the concept of which is often expressed in the picture's title, taken from musical terminology. Placing a painting's features in categories of 'musicality' may also have occurred at an earlier stage in the process of its reception through the subjective perception of critics and reviewers of the picture's properties as being 'musical'. In describing paintings critics may also draw on musical terminology. Both such phenomena as they appear in Polish painting and artistic critique at the turn of the 19th and 20th centuries are the object of the author's research. Polish artists perceived as 'painter-musicians' included, above all: A. Gawinski, M. Jakimowicz, J. Stanislawski, W. Wojtkiewicz and K. Stabrowski. The theory subjected to analysis of painting's 'musicalisation' as present in Polish art criticism at the turn of the 19th century should be acknowledged, in spite of its minimal influence on painting as it was practised, as an important phenomenon connecting Polish art with the main stream of European art at this time.