This article describes the First World War diaries of the King's African Rifles, one of the British African colonial regiments. The documents are held, together with other related material, at The National Archives, Kew, London. The content of these daily accounts of the activities of individual Units is discussed and their position within the structure of the archive is outlined, as is their relationship with certain other categories of War Office and Colonial Office records. It is suggested that the information contained in the war diaries might potentially contribute, apart from the military history of the East African campaign, to a social history of the regiment and to an environmental history of the campaign.