Anthracnose leaf spot of creeping woodsorrel (Oxalis corniculata), caused by Colletotrichum gloeosporioides, is reported for the first time in Brazil. The identity of the etiological agent was confirmed by a combination of morphological and molecular information. Koch's postulates were fulfilled with a selected isolate of this fungus obtained at Santa Maria, state of Rio Grande do Sul, Brazil. Keywords Fungal pathogen. Ocurrence. Creeping woodsorrel. Leaf spots Creeping woodsorrel (Oxalis corniculata) is a cosmopolitan species found in tropical and temperate areas, occurring as a weed in fields of beans, coffee, corn, potato and rice, where it can cause significant losses in yield. It is also present in grasslands, greenhouses, nurseries, and garden areas causing losses of plants (Hodi et al. 2014; CABI 2019). In addition, it may be an alternative host of pests and pathogens of crops (Guerra et al. 2016; Bellé et al. 2016). Colletotrichum includes a large number of plant pathogens of major importance, causing diseases and affecting production of horticultural crops, such as avocado, banana, citrus, mango, strawberry, but can cause devastating disease with as well as crops such as coffee, maize, sorghum and sugarcane (Cannon et al. 2012). Anthracnose symptoms include limited, often sunken, necrotic lesions on leaves, stems, flowers and