Green upconversion emission from Er3+(4f(11)) ion doped into a sol-gel silica glass under red light (647.1 nm) excitation has been observed and characterized. Green and weak blue emission bands, centered at 550 and 410 nm, for the S-4(3/2) --> I-4(15/2) and H-2(9/2) --> I-4(15/2) Er3+ transitions, respectively, have been observed. These upconversion processes involve a sequential two-photon absorption. A fluorescence efficiency of 1.7 x 10(-6) has been estimated for the S-4(3/2) --> I-4(15/2) (550 nm) emission in Er3+ ion at room temperature for a sample doped with 1.2 mol % ET(NO3)(3). An upconversion mechanism is proposed.