Ochratoxin A (OTA) is one of the most important mycotoxins owing to its widespread occurrence and toxicity including nephrotoxicity and potential carcinogenicity to humans. Since OTA is stable under most food processing conditions, OTA has been detected not only in a wide range of agricultural commodities such as cereal grains but also their processed products. Nonetheless, it is known that significant reduction of OTA may be achieved under higher temperature and alkaline conditions. In this study, the effects of retorting cooking process on the stability of OTA in spiked (20 μg/kg of dry weight basis) rice and oat porridge (10% solid content; w/v) in the presence and absence of baking soda was investigated using a laboratory horizontal steam retort system. The samples were heated in a pot at 85°C central temperature until it becomes gelatinized, packed in retort pouched, and heat-processed in pressurized retort machine (at 121°C for 25 min) followed by drying in 50°C oven overnight. Samples were analyzed for OTA by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The reduction of OTA in retorted rice and oat porridge were 54% and 17%, respectively, while greater reduction of OTA was observed at increased amount of baking soda. The reduction of OTA in retorted rice porridge with 0.5% and 1% baking soda were 55% and 66%, respectively. In the retorted oat porridge, reduction of OTA was also evident to result in 30% and 48% with 0.5% and 1.0% of added baking soda, respectively. These results suggest that OTA in rice and oat may be reduced significantly by retorting process. In addition, added baking soda may positively impact the reduction of OTA.