Trouble aligning text with WYSIWYG
If you're using the filtered HTML input format, that would be stripping it out.

If not, it sounds like your markup is weird. The way you describe it, what might work if it read &lt;p align="center"&gt; (not that I recommend this) reads &lt;p style="text-align:center"&gt;. I think WYSWIG editors tend to prefer classes to putting styles right in the markup, so I'd do something like &lt;p class="centered-text"&gt; and add .centered-text{ text-align:center } to your stylesheet.

I would double-check your site with a DOM inspector to make sure your style on your &lt;p&gt; isn't being overridden by a stylesheet. If nothing else works, you could use a different editor. jWYSIWYG, openWYSIWYG, Whizzywig, and nicEditor use align="wherever" instead of style="text-align:wherever" which might work (again, I don't recommend this, but it's a potential short-term solution. For reference, MarkItUp and WYMeditor don't offer alignment buttons, and CKEditor, FCKEditor, TinyMCE, and YUIeditor do it the "right" way, using style="")