Chinch bug, Blissus leucopterus leucopterus (Say) is an important pest of corn and attacks at the early stage of the crop, which may lead to deformation of corn seedlings such as “goosenecking” symptoms. A study is underway to investigate the biochemical changes associated with goosenecking symptoms using two dimensional gel electrophoresis and matrix assisted laser desorption ionization time-of-flight mass spectrometry. The initial results showed the differences in the protein expression patterns between healthy and chinch bug induced abnormal corn seedlings. Approximately 260 legible protein spots were detected using two-dimensional polyacrylamide gels. Protein expressions between two groups of the plants were similar. At least three proteins of 18-28 kDa were present only in healthy plants and one protein of about 28 kDa was up regulated in healthy plants. Similarly, two proteins of about 28 kDa were present only in abnormal corn seedlings and nine other proteins were up regulated in the abnormal seedlings. Identification and characterization of these proteins and the determination of their roles in abnormal seedling growth and development are currently underway.