Bioactive coatings were formed on alloy Ti6Al4V by plasma electrolytic oxidation (PEO) in two different electrolytes; a conventional Ca/P-based electrolyte and its modified version with added F and Si. Coatings formed after PEO for 90s, 180s, 300s and 600s were characterized with respect to their composition, structure, and morphology (SEM, EDX, XRD). Release of Ti, Al, V, Si, P and Ca ions was analyzed after 60 days of immersion in 0.9% NaCl solution. Coatings formed after PEO for 180s and 600s, with considerable differences in surface roughness and chemical composition (Ca/Ti, P/Ti, F/Ti ratios), were selected for further biological investigations. These involved Actin and Hoechst staining for monolayer formation evaluation, metabolic activity (Alamar Blue), evaluation of the osteoblastogenesis process (early osteogenic ability, ALP Assay, and collagen secretion) and biofilm formation (Staphylococcus aureus). All coatings equally well supported the growth and differentiation of murine osteoblast cells. The coating with the greatest content of fluoride demonstrated the most pronounced antibacterial effect with respect to S. aureus reducing the surface coverage down to 60% and leading to death of similar to 3% of bacteria. (C) 2018 Elsevier B.V. All rights reserved.