We granted Rockdale County’s application for discretionary review of the trial court’s ruling that the Rockdale County Board of Commissioners’ refusal to re-zone a .69-acre piece of property violated the property owner’s constitutional right to equal protection of the law. Because equal protection applies to similarly-situated property owners and the existence of a pre-existing nonconforming use prevents landowners from being similarly situated Puckett v. Paulding County , 245 Ga. 439 2 265 SE2d 579 1980, we reverse the trial court’s judgment. Appellee Michael Burdette, the owner of the property in question, sought rezoning in order to use the property as a small used-car sales lot, a use prohibited by the current C-1 “local commercial” zoning. He requested a change to C-2-conditional, a more intense “general commercial” use of the property, and he was willing to limit the more intense use to a particular use, a used-car sales lot containing a maximum of 15 cars. Burdette’s request was denied by the Board of Commissioners. He appealed the adverse decision to the superior court, where the trial court concluded the Board’s refusal to re-zone constituted a denial of equal protection. The trial court determined Burdette had suffered disparate treatment because the Board, on the same day it denied Burdette’s rezoning application, had taken action on a re-zoning application on a parcel five miles away which resulted in the second parcel being re-zoned from C-2 conditional limited to use as a used-car sales lot to C-1, with the condition that the owner be permitted to operate a small used-car lot as a legal nonconforming use. That owner had operated a small used-car lot on the property since 1989 when he had obtained a zoning classification of C-2 conditional, which limited the use to a small used car sales lot. Two years later, in 1991, Rockdale County adopted a comprehensive land use plan which called for both the used-car lot and Burdette’s parcel to be zoned C-1.