A 7-year-old male eclectus parrot (Eclectus roratus) was presented for evaluation of acute onset of dyspnea, tachypnea, and lethargy. Proventricular dilatation was observed on survey radiographs. Contrast fluoroscopic examination revealed decreased gastrointestinal motility and retention of contrast material in the proventriculus. Despite supportive care, the bird died. At necropsy, a tubular diverticulum of the ventriculus extended orad into the proventriculus. This diverticulum caused almost complete obstruction of proventricular outflow. No inflammation, infectious organisms, or neoplasia were associated with the lesion. The cause of the ventricular diverticulum in this parrot is unknown.