Melanolestes is a Nearctic and Neotropical genus of predatory reduviid bugs. It is revised and a diagnosis is given. The species up to date includes: M. argentinus Berg, M. degener Walker, M. morio Erichson, M picicornis StÅl, M. picinus StÅl and M. picipes (Herrich-Schaeffer) and all are redescribed. Three new species, M. goiasensis, M. lugens and M. minutus, are described. A key is presented and the main taxonomic characters (head, pronotum, scutellum, male and female genitalia) are illustrated. Distribution maps and a table with measurements and ratios are included.