The production of metastable O(1S) atoms by the dissociative recombination of O2+ ions has been studied in a laboratory plasma spectroscopy experiment. The specific dissociative recombination coefficient for O(1S) formation has a value of 2.1¿10-8 cm3 s-1, corresponding to an O(1S) quantum yield of 10% at an apparent temperature of 296 ¿K, in agreement with the earlier but less comprehensive measurements of Zipf [1970>. By using a variety of gas mixtures in order to modify the vibrational pupulation of the O2+ ions and laser-induced photofluorescence techniques it was found that the laboratory O2+ plasmas are vibrationally excited and that O2+ ions in the &ngr;'=4--12 vibrational levels are the chief source of the observed O(2S) atoms. The specific O(1S) dissociative recombination coefficient for O2+(2&pgr;g) ions in the lowest vibrational levels (&ngr;'?3) is much smaller (4.2¿10-9 cm3 s-1). The implications of the quantum yield of 9.9% derived from Atmosphere Explorer data are discussed in the light of these findings. Preliminary electron-heating experiments indicate that the specific O(1S) recombination coefficient decreases with increasing electron temperature.