This volume contains the proceedings of the Second International Workshop on Mobile Entity Localization and Tracking in GPS-less Environments (MELT 2009), held in Orlando, Florida on September 30, 2009 in conjunction with the 11th International Conference on Ubiquitous Computing (Ubicomp 2009). MELT provides a forum for the presentation of state-of-the-art technologies in mobile localization and tracking and novel applications of location-based s- vices. MELT 2009 continued the success of the ?rst workshop in the series (MELT 2008), which was held is San Francisco, California on September 19,...