The aim of this thesis is to describe and evaluate the usability of two Swedish systems, Sofie and Carlotta, which are used to organize and present data regarding museum objects on the web. This thesis also presents how objects are described and made accessible to the public in the two systems. To evaluate the usability, a heuristic method combined with Systematic Usability Evaluation has been used. The description and accessibility of object representations in the systems are evaluated using indexing and classification theories from the field of Library and Information Science. Additional theoretical background that has been used is how users search and browse information systems.