We investigated the nest structure and nesting habits of Polyrhachis muelleri Forel, 1893 in Eastern Thailand where we found 23 colonies dwelling and nesting in the shrub layer about 1.0 - 4.5 m above the forest floor. They construct their nests on the underside of broad - leaves of different tree species. The nests were constructed of a loose and thin pure silk possessing an oval or elliptic shape. The present paper recorded a new distribution for this ant species in Thailand at Khao Soi Dao Wildlife Sanctuary, Chanthaburi province and also recorded new host plants. Nest structure and nesting habits are discussed in comparison with those of other Polyrhachis and other genera.