Abstract The first successful growth of YFe 2O 4 single crystals was carried out by the floating zone method. The atmosphere to give suitable oxygen partial pressures for the crystal growth of YFe 2O 4 was determined. The mixtures of CO 2 and H 2 with the mixing ratio ranging over CO 2 H 2 = 0.65 – 0.95 , or the equivalent CO 2CO mixtures, and the growth speed of 2 mm/hour or slower were found to be the essential conditions. The as-grown boules were aggregates of large single crystal grains with the c-axes perpendicular to the growth direction. A typical separated single crystal was a rectangular chip of 3mm × 1.5mm × 0.5mm. A slower growth speed is suggested for obtaining a bigger single crystal.