What is an "in care of" address?

An "in care of" address is a way to send a letter to a recipient who is temporarily staying somewhere else or receiving mail somewhere else. The proper way to address the letter is to write, for example, "C/O John Smith" under the name of the actual recipient.

Using an "in care of" address to send a letter is the proper method to use if there is concern that the postal service may not deliver the mail with an unfamiliar name. When addressing the envelope, the information for the recipient is written at the center and the upper left-hand corner bears the sender's name and address.