Insurance Company v. Mosley was a case heard by the United States Supreme Court in 1869. The case involved a dispute between an insurance company and a policyholder over the validity of a life insurance policy. The policyholder, Mosley, had purchased a life insurance policy from the insurance company, but the company refused to pay out the policy when Mosley died. The insurance company argued that the policy was invalid because it had been procured through fraud. The Supreme Court ruled in favor of Mosley, finding that the insurance company had failed to prove that the policy was procured through fraud. The Court held that the insurance company had the burden of proving that the policy was procured through fraud, and that the company had failed to meet that burden. The Court also held that the insurance company was not entitled to rescind the policy, as it had failed to prove that the policy was procured through fraud. The Court's ruling in Insurance Company v. Mosley established that an insurance company must prove that a policy was procured through fraud in order to be able to rescind the policy. The ruling also established that the burden of proof lies with the insurance company, and that the company must prove that the policy was procured through fraud in order to be able to rescind the policy.

In Insurance Company v. Mosley, the Supreme Court was tasked with determining whether an insurance company could be held liable for a policy issued to a slaveholder that covered his slaves as property. The majority opinion found that the insurance company had no liability because it did not have knowledge of any illegal activity associated with the policy and thus should not be held responsible for any damages caused by such activity. However, in dissent Justice Field argued that since slavery is illegal under both state and federal law, it follows logically that an insurance contract covering slaves would also be invalidated on those grounds alone regardless of whether or not the insurer knew about its illegality at the time of issuance. He further stated that if insurers are allowed to issue policies without regard to their legality then they will become complicit in perpetuating unlawful activities like slavery which undermines public morality and justice.