Abstract: A mail delivery indicator which may be readily and easily mounted on the standard rural or cluster mailbox to signal when the mail has been delivered by the mail carrier. The mail delivery indicator comprises an elongated rod forming a flag staff with one of its ends connected to a coiled spring attached by a bracket to the right side of the mailbox. The other end of the flag staff is provided with a flag member and a latch element. The latch element serves the dual purpose of securing the flag to the flag staff and engaging a catch element on the mailbox door to set the flag staff in its horizontal nonsignaling position when the door is closed. When the door is opened by the mail carrier, the latch element releases from the catch element and the coiled spring causes flag staff to automatically swing to its vertical signaling position.