Rising customer expectations asking for highly customized products and short delivery lead times is putting under great pressure production and logistic systems, which are forced to become more flexible and reactive to demand requirements. On the market a wide range of options is present and new solutions are continuously introduced. This work thesis is divided in two main steps. First, after a general academic introduction on warehousing and storage systems, a thorough analysis of all the existing storage technologies for both pallet unit loads and small unit loads is conducted, in order to gain insights into the alternatives currently available and to highlight their strengths and weaknesses.