Optimization of chemical kinetic modeling for biobutanol oxidation requires further investigation on its key stable intermediates, such as aldehydes. In this study, ignition delay times of isobutanal/oxygen diluted with argon were measured behind reflected shock waves in the temperature range of 1100-1650 K, at pressures of 1.3, 5, and 10 atm, and equivalence ratios of 0.5, 1.0, and 2.0. An isobutanal submodel was developed on the basis of literature review, and it yields fairly good agreement with the experimental results under the test conditions. The reaction pathway and sensitivity analysis were performed to gain insight into the controlling reaction pathways and reaction steps.