Oud Ade is a village in the Dutch province of South Holland. It is a part of the municipality of Kaag en Braassem, and lies about 7 km east of Leiden. In 2001, the town of Oud Ade had 336 inhabitants. The built-up area of the town was 0.04 km2, and contained 119 residences. The wider statistical district "Oud Ade and Zevenhuizen" has a population of around 620.