Two new digenean species are described from the intertidal blenny Scartichthys viridis (Valenciennes) (Blenniidae) collected off the coasts of Chile. The digenean Monorchimacradena viridis n. sp. (Lecithasteridae: Macradenininae) differs from the only known species described in the genus, M. acanthuri Nahhas and Cable 1964, in the presence of Drüsenmagen in the caeca, the location of the seminal vesicle between the testis and ovary (anterior to the testis in M. viridis n. sp.), and the pre-ovarian vitellarium. Megasolena littoralis n. sp. (Haploporidae), which is also reported from Scartichthys gigas (Steindachner), differs from the five valid species of Megasolena in that the post-caecal region (from the posterior edge of the caeca to the end of the body) is larger in M. viridis n. sp., meaning that the caeca are shortest in this species. Also, M. littoralis n. sp. is distinguished, from the other congeneric species, in a combination of characteristics, e.g., body length, suckers, pharynx, testes, hermaphroditic sac and sucker-length ratio. Sequences of ITS2 rDNA were generated for specimens of both species from various localities, indicating that it was invariant within the species. This study describes species of Monorchimacradena and Megasolena in Chilean waters, here reported for the first time off the Pacific Coast of South America.