Asymmetric key algorithms use different keys for encryption and decryption. The keys are: Private Key and Public Key. The encryption key is public, decryption key is secret. Anyone can encrypt a message but only the one who knows the corresponding private key can decrypt it. The decryption key cannot be derived from the encryption key. Asymmetric key algorithms used for transmitting encryption keys or other data securely even when the parties have no opportunity to agree on a secret key in private. This paper discuss about some asymmetric key algorithms with its advantages and disadvantages.