When using MathML embedded in an HTML page (as opposed to XHTML), there are some issues you need to keep in mind: Since self-closing tags are not part of HTML, you need to be sure all your MathML tags have both an open and a close tag: <mspace width="1em"></mspace> not <mspace width="1em" />. Use numeric entities rather than named entities: &#x222B; not &Integral; Details about MathML support in HTML pages