<div class="valign" style="height: 500px">
	<div class="vertical">
		<div id="center">
			This line will be vertically centered at 250px inside a 500px high DIV
		</div>
	</div>
</div>


/* Vertical align -- You must specifiy height on "valign" element */
.valign				{ position: relative; }
.valign[class]			{ display: table; position: static; }
.valign .vertical		{ position: absolute; top:  50%; }
.valign .vertical[class]	{ display: table-cell; vertical-align: middle; position: static; }
.valign .center			{ position: relative; top: -50%; }
.valign .center[class]		{ position: static; }

[via rtcrm]

This will vertically align a block-level element inside a fixed-height containing block-level element. Note: you must know the exact pixel height of the containing element!

Vertically align within fixed height DIV

CSS