Novel spiro [indoline-3,9'-tetrazolo[5,1-b]quinazoline]-2,8'(5'H)-dione derivatives have been synthesized by the threecomponent reaction of isatin, 5-amino-1H-tetrazole, and 5,5-dimethylcyclohexane-1,3-dione in PEG-H2O medium catalyzed by p-TSA. This protocol provides a simple one-step procedure with the advantages of easy work-up, mild reaction conditions, and environmental benignity.