Cardano is a public decentralized blockchain platform which uses the cryptocurrency, ADA, to facilitate transactions.

Cardano's development began in 2015. When launched in 2017, it was the largest cryptocurrency to use a proof of stake blockchain. A number of independent entities collaborate on the project, including the Cardano Foundation based in Zug, Switzerland and led by its chief executive officer Frederik Gregaard.

After leaving Ethereum in 2014, Charles Hoskinson and Jeremy Wood set out their plans for establishing Cardano in 2015. Hoskinson had left Ethereum after a dispute with another co-founder, Vitalik Buterin; Hoskinson wanted to accept venture capital and create a company, while Buterin wanted to keep it as a nonprofit organization. Wood and Hoskinson co-founded the business IOHK to develop blockchains for use by corporations, governments, and education institutions.

Cardano was initially released to the public in 2017. That year, IOHK partnered with the University of Edinburgh to launch the Blockchain Technology Laboratory. The lab had six post-doctoral and professorial positions with up to 35 jobs created in total, and was led by Aggelos Kiayias, developer of the Ouroboros protocol.

Cardano reached a market cap of $77 billion in May 2021, which was the fourth highest for a cryptocurrency at that time.

Advertising agency MBLM ranked Cardano 26th for brand intimacy out of 600 brands in August 2022, in between Ford and Nestlé and the highest rank for a cryptocurrency. Citing an MBLM partner, advertising industry magazine Ad Age said Cardano's high ranking "can likely be chalked up to the gambling element of crypto".

The platform is named after Italian mathematician Gerolamo Cardano, while the cryptocurrency itself is named after the English mathematician Ada Lovelace. The Ada sub-unit is the Lovelace; one Ada = 1,000,000 Lovelaces.

Cardano was originally controlled by three entities: