In contrast to more traditional studies of “prose” rhythm, the present work introduces an empirically derived notion of conversational speech rhythm as auditory gestalt, for which however rough acoustic guidelines can be determined, and investigates the occurrence and distribution of rhythmically organized patterns of prosodic prominence in a moderate-sized corpus of everyday English conversation. The author argues that speech rhythm creates a metric according to which the timing of turn transitions in English conversation is judged, and presents ethnomethodological evidence that shows which conversationalists themselves orient to a rhythm-based metric. Speech rhythm can thus be seen as a resource which interactants have at their disposal for the prosodic contextualization of their verbal messages.