This article explores the use of private diaries in qualitative research about intimate everyday experiences. The article first reflects on existing diary-based research, then examines data from a small-scale UK study about the negotiation of condom use in heterosex to pose questions about the kinds of data made available when participants use private diaries as a prompt in qualitative interviews. The article discusses the use of private diaries as a way to explore ambivalent, everyday experiences and interrogates the role of diaries as a form of confessional or measurement of private life. It explores how combined researcher intimate diaries and field note journals can be used in reflexive qualitative sexualities research. The article finally examines the potential for diaries as a form of research intervention in participants’ intimate lives.