This paper addresses Newman's understanding of conscience and authority, with the main emphasis on conscience. It asks how central a place conscience holds in his theological understanding? Is the general high esteem in which Newman's perception of conscience is held – and by some even regarded as one of the integral elements of his thinking, providing it with an inner consistency – justified? Finally the relationship between conscience and authority is explored. John Henry Newman's teaching on conscience and authority is a complex but highly pertinent question which continues to enthral many, not least Pope Benedict XVI who has hailed Newman's understanding of conscience as ‘an important foundation for theological personalism’. Newman denounced the modern secularized and purely subjective understanding of conscience as he perceived it to be ‘the voice of God’. He focused his writings on conscience within the contexts of morality and theology and considered the role that conscience may play in moral decision-making and in establishing a person's belief in God. In Newman's legendary dispute with W. E. Gladstone in the 1870s the Cardinal maintained that there is no contradiction between the conscience of the individual and the authority of the Pope or of the church, as they occupy two different spheres.