Rhodococcus equiis a Gram-positive facultative intracellular bacterial pathogen that primarily infects macrophages. It is considered to be the most important cause of pneumonia in foals aged three weeks to five months, and affects foals worldwide. While its prevalence in the UK is unknown, anecdotal evidence suggests that morbidity and mortality on affected premises can be high. Over the past several decades, knowledge of the pathogenesis, virulence, immunity and treatment of R equi pneumonia has advanced significantly, resulting in improved survival rates and preventive strategies. However, despite these advancements, an effective vaccine has yet to be developed, and newer challenges, including the emergence of antimicrobial-resistant R equi and effective management of subclinically affected foals, have been identified. This article gives an update on how to diagnose the condition, the various treatments available and possible preventive measures.