The position of the lowest empty orbitals of CO and O chemisorbed on Ni(111) have been determined by use of inverse photoemission in the ultraviolet. The $2{$π${}}^{*}$ orbital of CO is lowered by 4.5 eV upon chemisorption and broadened to a 5.5-eV-wide resonance centered 3.5 eV above ${E}_{\mathrm{F}}$. Chemisorbed oxygen has sharp $2{p}_{x,y}$ states at 1.4 eV above ${E}_{\mathrm{F}}$ at ${k}_{$∥${}}=0$ with the total density of states extending from ${E}_{\mathrm{F}}$ to ${E}_{\mathrm{F}}+2$ eV in agreement with band calculations. This state disappears upon oxide formation.