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Abstract. The purpose of the study was to validate effects of radio frequency (RF) heating under controlled atmosphere (CA) on thermal inactivation of E. coli ATCC 25922 in almond kernels. A 2.4 kW, 27.12 MHz, 50 Ω RF heating system was used to treat 1.5 kg size almond kernel samples with the adjusted moisture content of 8.0% wet basis under regular atmosphere (RA, 21% O₂, 79% N₂) and CA (2% O₂, 20% CO₂, 78% N₂) conditions. The power level of 900 W under an electrode gap of 11.5 cm was used at the ramping stage for quick heating, and a maximum temperature difference of 3 °C in the inoculation area was achieved by reducing the RF power during the holding stage. The 4-log reduction time under CA treatment was achieved with 21 ± 1 min holding at 75 ± 3 °C, resulting in 38% of RF heating time as compared with RA environment. The quality attributes of treated samples remained within acceptable range based on nut industry standards. The RF heating under CA conditions therefore may hold potential as an effective treatment method to control E. coli ATCC 25922 in raw almond kernels and be possibly extended for pasteurization applications.