diff --git a/src/mathed/InsetMathExInt.cpp b/src/mathed/InsetMathExInt.cpp
index 5313f0adc3..bc26c05f53 100644
--- a/src/mathed/InsetMathExInt.cpp
+++ b/src/mathed/InsetMathExInt.cpp
@@ -124,11 +124,41 @@ void InsetMathExInt::mathematica(MathematicaStream & os) const
 
 void InsetMathExInt::mathmlize(MathStream & os) const
 {
+	if (symbol_ == "sum") {
+		bool const lower = !cell(1).empty();
+		bool const upper = !cell(3).empty();
+		if (lower && upper)
+			os << MTag("msubsup");
+		else if (lower)
+			os << MTag("msub");
+		else if (upper)
+			os << MTag("msup");
+		os << MTag("mrow") << MTag("mo") << "&sum;" << ETag("mo") << ETag("mrow");
+		if (lower) {
+			os << MTag("mrow");
+			os << cell(1);
+			if (!cell(2).empty())
+				os << MTag("mo") << "=" << ETag("mo") 
+				   << cell(2);
+			os << ETag("mrow");
+		}
+		if (upper)
+			os << MTag("mrow") << cell(3) << ETag("mrow");
+		if (lower && upper)
+			os << ETag("msubsup");
+		else if (lower)
+			os << ETag("msub");
+		else if (upper)
+			os << ETag("msup");
+		os << cell(0);
+		return;
+	}
+	// some kind of integral
 	InsetMathSymbol sym(symbol_);
 	//if (hasScripts())
 	//	mathmlize(sym, os);
 	//else
-		sym.mathmlize(os);
+	sym.mathmlize(os);
 	os << cell(0) << "<mo> &InvisibleTimes; </mo>"
 	   << MTag("mrow") << "<mo> &DifferentialD; </mo>"
 	   << cell(1) << ETag("mrow");