Fungi of the genus Cyathus are popularly known as “bird’s nest fungi” and are characterized by the presence of bell-shaped or inverted cone-shaped basidiomata, with a smooth wall surface or having vertical striations, in addition to small lenticular structures inside, the peridioles. Cyathus belongs to the family Nidulariaceae together with the genera Mycocalia Palmer, Nidularia Fr., Nidula V.S. White and Crucibulum Tul. & C. Tul; of which Cyathus is the most representative. The state of Bahia has points of great biodiversity and endemism, such as Chapada Diamantina, with phytophysionomies of rupestrian fields, ‘cerradão’, among others, and the coastal region, where the Atlantic Forest predominates. This work aimed to survey the taxonomic richness of fungi of the genus Cyathus in Atlantic Forest and Cerrado fragments of Bahia, in northeastern Brazil, as well as to expand the collection of fungi from the ALCB. Macro and microscopic morphological studies were carried out, as well as molecular studies for the new species for science. The ITS region was amplified using ITS1 and ITS4 primer combinations. For the molecular studies, phylogenetic analysis was performed with data concatenated in PAUP and MrBayes, with Maximum Parsimony and Bayesian analysis, respectively. 12 species of the genus Cyathus were identified, namely: C. discoideus as the first record for the Americas; C. costatus as the first record for Brazil; C. morelensis and C. stercoreus as the first record for Northeast Brazil; Cyathus badius, C. earlei, C. hortensis, C. triplex, as the first record for the state of Bahia; and C. striatus and C. limbatus. as the second record for the state of Bahia. Cyathus mucugensis and C. torrendii are proposed as new species for science. In addition to these, three samples were identified only at the gender level. The results obtained are of great relevance for the knowledge of the Brazilian northeast funga, serving as subsidy for conservation projects and sustainable use of Brazilian biomes.