The Pahang Mud Snake (Kualatahan pahangensis) (Tweedie 1946) is a rare species of homalopsid known only from four specimens. In this study we report on a relatively recently collected specimen from Merapoh, Pahang, Peninsular Malaysia, compared with previously collected material. Variations in pholidosis and colour pattern were noted and discussed. The species is morphologically similar in body shape and colour pattern to the sympatric Hypsiscopus plumbeus, for which additional data is presented for Peninsular Malaysian specimens to clarify possible taxonomic confusions. The new record represents a range extension for the species of ~ 47 km to the west and is the third report of the species from the state of Pahang.