Fruits of blackberry are recognized as a rich natural source of polyphenolic substances which may provide health benefits. As its consumption is increasing, crop breeding plays an important role in the search for new cultivars which may offer better production, quality and healthier benefits.1 In this context, it is important to evaluate, besides the physicochemical properties and fruit production data, the presence of anthocyanins and other phenolic substances which are related to the known antioxidant activity of blackberry fruits. In this work, fruits of two breeding selections (Black 145 e Black 178) and three cultivars (Tupy, Xingu and Xavante) of Rubus spp. cultivated in Curitibanos, Santa Catarina, Brazil, were evaluated to their total Phenolic (TPC) and total monomeric anthocyanins (TMAs). Plant seedlings were provided by Embrapa Temperate Agriculture and stablished, in august 2015, in the agricultural experimental area of Federal University of Santa Catarina at Curitibanos campus. The experimental design was planned using three plots with five seedlings each cultivar or selection. Fruits of each selection or cultivar were collected, in a time period from december till February, years 2016 and 2017, by randomly picking and stored at freezer. Berries from each Breeding selection or cultivar were macerated and weighted (50 g) in order to prepare the extracts. Ethanol 96% (100 mL) was added to the macerated fruits and the mixture was acidified with concentrated HCl to pH 1.5. Then, the solution was left in the fridge for 12h and centrifuged. The supernatant was separated and evaporated to give the crude extracts (CE) which were submitted to total phenolic content (TPC) and total monomeric anthocyanins (TMAs) assays. The TPCs of different CEs were measured using the Folin–Ciocalteu method3 and gallic acid (GA) was used as standard. The absorbance was measured at 725 nm and results were expressed as milligrams of GA equivalent (GAE) per g of dry extract: Black 145: 9,214; Black 178: 11,94; Tupy: 11,94; Xingu: 8,31; Xavante: 19,38. The TMAs were determined using the pH-differential method4 and cyanidin-3-glucoside was used as standard. The absorbance was measured at 520 and 700 nm in buffers at pH 1.0 (0.025 M potassium chloride buffer) and 4.5 (0.4 M sodium acetate buffer). The anthocyanin concentrations were presented as milligrams of standard per 100 g of dry extract: Black 145: 193,19; Black 178: 216,48; Tupy: 144,07; Xingu: 159,93; Xavante: 109,21. Results showed important differences between breeding selections/cultivars where higher TPC was found for the cultivar Xavante and higher TMA for the breeding selection Black 145. Preliminary HPLC analysis show some differences on the composition of phenolic substances but low concentration of the components which indicate that the extraction procedure was perhaps not efficient. Other procedures are going to be tested in order to extract substances with antioxidant activity in higher concentration.