An inbred corn line, designated LH321, is disclosed. The invention relates to the seeds of inbred corn line LH321, to the plants of inbred corn line LH321 and to methods for producing a corn plant, either inbred or hybrid, by crossing the inbred line LH321 with itself or another corn line. The invention further relates to methods for producing a corn plant containing in its genetic material one or more transgenes and to the transgenic plants produced by that method and to methods for producing other inbred corn lines derived from the inbred LH321.