In the catalytic oxidation of isobutylene and/or tertiary butyl alcohol to methacrolein, the product methacrolein is recovered as an aqueous solution, which thereafter is stripped of methacrolein by contacting the solution with recycle gases from the subsequent oxidation of methacrolein to methacrylic acid. In a preferred embodiment, the oxidation reactor effluent gases are quenched to near ambient temperatures by direct contact with a recirculating stream of partially condensed effluent to provide an aqueous solution of methacrolein and thereafter the methacrolein remaining in the effluent gases is absorbed into a refrigerated water stream to provide a second aqueous solution. The aqueous solutions are combined and stripped by recycle gases, thereby supplying methacrolein as feed to the subsequent oxidation process.