Propensity evidence remains one of the most obscure areas of evidence law. The uncertainty concerning its admissibility stems largely from a failure to identify the precise forms that such evidence may take and the exact dangers typically associated with each type of propensity evidence. Propensity evidence comes in three basic forms: similar fact evidence; relationship evidence; and where it is part of the res gestae. This article focuses on relationship evidence and res gestae propensity evidence and examines the circumstances in which such evidence should be received. The jury directions that ought to accompany such evidence are also considered.