This article examines the emergence of professional liability and forensic science in the context of the Lex Aquilia. The interpretations of jurists, found in the sections of the Digest discussing the Lex Aquilia, subjected professionals to a higher standard of responsibility and liability, both in the context of locatio-conductio contracts and outside of it. At the same time, the Roman legal system increased its reliance on professionals for determining factual issues in legal disputes. The examples of public physicians, who were dispatched to examine suspicious acts of violence; midwives, who were appointed by the court to determine contested paternity or maternity; and land-surveyors, who presided over boundary disputes, are amongst the most common. This article examines the inter-relation between legislation originating in the Lex Aquilia and the emergence of professional liability on the one hand, and the evolution of forensic science on the other hand.