The present study evaluated the use of a pressurized method to extract phycobiliproteins from the cyanobacterium Arthrospira platensis using sodium phosphate buffer as an extracting solution. Phycobiliprotein extracts were characterized and their antioxidant and anticancer activities (on different cancer cell lines) were determined. A high extraction yield was obtained when high pressure was used, without any alteration of the molecules’ biofunctionality. Maximum phycocyanin and allophycocyanin concentrations obtained (at 100 bar after 360 min) were 4.44 g L −1 and 1.63 g L −1 , respectively. The purity indexes of extract were 3.59 (A 615 /A 280 ) for phycocyanin and 1.72 (A 652 /A 280 ) for allophycocyanin. The purified phycobiliprotein extract showed high antioxidant activity, with 98% in the reduction of 2,2-diphenyl-1-picryl-hydrazil (DPPH) radicals and 100% in the chelation of ferrous ions, and it presented in vitro anticancer activity for HL60 leukemic cells.