The spleen is an intraperitoneal organ which is composed of a trabecular network of vessels, nerves and lymphatic tissue. Anatomical variants with regard to the shape and accessory spleens are seen. Systemic lymphatic diseases often result in splenomegaly. There are a number of different focal cystic or solid lesions, which can be found in the spleen in various pathological conditions. These are often inflammatory, but also neoplastic or developmental lesions are found. The following chapter will present the most common focal and diffuse pathologies of the spleen with special emphasis on their CT appearance.