The first records of terrestrial planarians belonging to the family Rhynchodemidae are reported for the Iberian Peninsula. A new endemic species from the Spanish Pyrenees, Microplana nana sp. nov. is described. The characteristic features of this species are: i) small size (8-10 mm) in adult individuals, ii) very long conical penis papilla and iii) absence of seminal vesicle, bursa copulatrix, genito-intestinal duct, and well developed penial bulb. Moreover, the widespread common European land planarian Microplana terrestris (Müller, 1774) is reported for the first time from the Iberian Peninsula. The two species, M. nana sp. nov. and M. terrestris are described by means of external morphology, histological sections, and have been characterized using the ITS-1 molecular marker. The study of molecular markers such as ITS-1 is proposed as a powerful technique for identification at the species level in terrestrial planarians.