This paper represents an initial attempt to provide theoretical structure for the sociological study of sadomasochism. Sadomasochistic behavior, like human behavior in general, is most fully understood within a social context. To understand "what is going on" within an S&M episode, one must know something about the culture of the group and how it defines and categorized people and behavior. This is where frame analysis is helpful. Frames are central components of the culture of the group, through which its members interpret the world. To a great extent the frame itself is structured by the language of the groups, which serves to explain to its members what is happening and to justify their desires, motives, and behavior. Frames tell people what is and what is not proper, acceptable, and possible with their world. They define and categorize for their members situations, settings, scenes, identities, roles, and relationships. When people join sadomasochistic groups, or any other kind of group, they are taught not only frames, but also the conceptual tools or "keys" for defining, applying, transforming, and limiting them. Frame analysis helps make sense of findings that might otherwise be difficult to explain. For example, the apparently puzzling existence in the S&M subculture of "dominant" women and "submissive" men when the larger society to which these individuals also belong prescribes aggressiveness for males and passivity for females may be explained in terms of makebelieve, fantasy, and the theatrical frame. Lack of generalization into the larger world of roles and relationships developed within the sadomasochistic subworld is explained in terms of how behavior is "keyed". A number of areas that have not been fully developed here could be profitably explored. For example, although we have attended to the structuring and limiting of S&M frames, we have not explored misframings, miskeyings, breaking frame, and other errors and their consequences for interactants. Hollander, for instance, provides an example in which an S&M episode was miskeyed with disastrous results. Another issue for further exploration involves the ways in which the language of S&M structures the relations between participants in the world by building in notions of activity and passivity and tying these to particular roles in the interaction. The specific identities of people as "dominant" or "submissive", the ways in which they arrive at a recognition of these self-identities, and the stability of these orientations await investigation.