Disclosed is an image sensor including a photo-sensing device, a color filter positioned on the photo-sensing device, a microlens positioned on the color filter, and an insulation layer positioned between the photo-sensing device and the color filter, and including a trench exposing the photo-sensing device and a filler filled in the trench. The filler has light transmittance of about 85% or more at a visible ray region, and a higher refractive index than the insulation layer. A method of manufacturing the image sensor is also provided.