Thirteen species of Heteroceridae representing two genera (Heterocerus and Tropicus) were found to occur in Mississippi, including one new species in the genus Tropicus. Collection data has been compiled from material housed at the California Academy of Science, the University of Mississippi and Mississippi State University. Collecting efforts were focused on riparian habitats throughout Mississippi during the summers of 2003 and 2004. Geographic and seasonal distributions are presented for each species. Of the species occurring here, two are generally distributed throughout the US, seven are widely distributed in the East, one is primarily mid-western in distribution, one is known almost exclusively from Florida and another almost exclusively from Mississippi. The undescribed species of Tropicus occurs in Mississippi, Florida and South Carolina