Although often presented as an essential, ahistorical or innate psychological entity, the notion of a 'scientific mind' is ripe for historical analysis. The growing historical interest in the self-fashioning of masculine identities, and more particularly the self-fashioning of the nineteenth-century scientist, has opened up a space in which to probe what was understood by someone being said to possess a 'scientific mind'. This task is made all the more urgent by the recently revived interest of some psychologists in the concept and the highly gendered and culturally conditioned understanding of the scientific mind displayed in some contemporary debates. This article contributes to that task, and fills a rare gap in Darwin studies by making the first detailed exploration of Charles Darwin's understanding of the scientific mind, as revealed in the psychological self-analysis he undertook in his 'Recollections of the development of my mind and character' (1876), and supplemented in his Life of Erasmus Darwin (1879). Drawing upon a broad range of Darwin's published and unpublished works, this article argues that Darwin's understanding of the scientific mind was rooted in his earliest notebooks, and was far more central to his thought than is usually acknowledged. The article further delineates the differences between Darwin's understanding and that of his half-cousin Francis Galton, situates his understanding in relation to his reading of William Whewell and Auguste Comte, and considers what Darwin's view of the scientific mind tells us about his perspective on questions of religion and gender. Throughout, the article seeks to show that the 'scientific mind' is always an agglomeration of historically specific prejudices and presumptions, and concludes that this study of Darwin points to the need for a similarly historical approach to the question of the scientific mind today.