Express Company v. Caldwell is a United States Supreme Court case that was decided in 1875. The case involved a dispute between the Express Company and Caldwell, a former employee of the company. The Express Company had sued Caldwell for breach of contract, claiming that he had failed to fulfill his contractual obligations. The Supreme Court held that the Express Company was not entitled to damages from Caldwell. The Court found that the contract between the parties was not valid because it was not in writing and was not signed by both parties. The Court also found that the Express Company had failed to prove that Caldwell had breached the contract. The Court's decision was based on the Statute of Frauds, which requires certain contracts to be in writing and signed by both parties in order to be enforceable. The Court held that the Express Company had failed to meet this requirement and, therefore, was not entitled to damages from Caldwell.

In Express Company v. Caldwell, the Supreme Court was tasked with determining whether a state statute that prohibited express companies from charging more than two percent commission on money orders violated the U.S. Constitution's Commerce Clause and Contract Clause. The majority opinion held that it did not violate either clause, but Justice Field dissented in part because he believed that Congress had exclusive authority to regulate interstate commerce and thus any regulation of such commerce by a state was unconstitutional under the Commerce Clause. He also argued that since this law interfered with contracts between parties who were citizens of different states, it violated the Contract Clause as well as Article I Section 10 of the Constitution which prohibits states from passing laws impairing contractual obligations without just compensation being provided to those affected by them. Ultimately, Justice Field concluded that while there may be some valid reasons for regulating certain aspects of interstate commerce at a local level, they must still comply with constitutional requirements or else risk infringing upon federal powers granted exclusively to Congress under Article I Section 8 of the Constitution