Cell viability and in vitro osteoblast cell responses to characterized anatase and rutile titania nanofiber scaffold surfaces were investigated. Poly(vinyl acetate) (PVAc)/titanium isopropoxide (TIP) composite microfibers with average fiber diameter of about 3 μm were fabricated via electrospinning. The microfibers were calcined to 500 and 900 °C to obtain the anatase and rutile phase titania (TiO2) nanofibers of about 500 nm diameter. The weight loss pattern of PVAc/TIP microfibers was determined by simultaneous thermo-gravimetric analysis (TG-DTA). The morphology of fibers was characterized by scanning electron microscopy (SEM). X-ray diffraction (XRD) and Raman spectroscopic analysis confirm the varied phases of the fibers formed at different calcination temperatures. The obtained nanofibers by well conceived heat treatment showed the fibers to have rough surface that could be shaped by sintering of crystalline titania nanoparticles. MTT reduction calorimetric assay using vero cells; cell adhesion and proliferation study using osteoblast cells indicated a notable difference in cell viability and osteoblast cell response to the sintered fibers with rutile phase showing improved properties for scaffold applications compared to anatase. Thus, the biological evaluation of phase controlled titania nanofibers indicated that rutile phase could serve as a better candidate for tissue engineering applications. © 2012 American Scientific Publishers. All rights reserved.