Andres Ilich has it right. Just in case someone misses his comment...
A.) If you only have one line of text:
div_x000D_
{_x000D_
height: 200px;_x000D_
line-height: 200px; /* <-- this is what you must define */_x000D_
}
_x000D_
<div>vertically centered text</div>
_x000D_
B.) If you have multiple lines of text:
div_x000D_
{_x000D_
height: 200px;_x000D_
line-height: 200px;_x000D_
}_x000D_
_x000D_
span_x000D_
{_x000D_
display: inline-block;_x000D_
vertical-align: middle;_x000D_
line-height: 18px; /* <-- adjust this */_x000D_
}
_x000D_
<div><span>vertically centered text vertically centered text vertically centered text vertically centered text vertically centered text vertically centered text vertically centered text vertically centered text vertically centered text vertically centered text</span></div>
_x000D_