diff --git a/Classes/PHPExcel/Calculation.php b/Classes/PHPExcel/Calculation.php
index 152c98e..19e8edd 100644
--- a/Classes/PHPExcel/Calculation.php
+++ b/Classes/PHPExcel/Calculation.php
@@ -3557,15 +3557,37 @@ class PHPExcel_Calculation {
 		if (is_string($operand1) && $operand1 > '' && $operand1{0} == '"') { $operand1 = self::_unwrapResult($operand1); }
 		if (is_string($operand2) && $operand2 > '' && $operand2{0} == '"') { $operand2 = self::_unwrapResult($operand2); }
 
+		// Use case insensitive comparaison if not OpenOffice mode
+		if (PHPExcel_Calculation_Functions::getCompatibilityMode() != PHPExcel_Calculation_Functions::COMPATIBILITY_OPENOFFICE)
+		{
+			if (is_string($operand1)) {
+				$operand1 = strtoupper($operand1);
+			}
+
+			if (is_string($operand2)) {
+				$operand2 = strtoupper($operand2);
+			}
+		}
+
+		$useLowercaseFirstComparison = is_string($operand1) && is_string($operand2) && PHPExcel_Calculation_Functions::getCompatibilityMode() == PHPExcel_Calculation_Functions::COMPATIBILITY_OPENOFFICE;
+
 		//	execute the necessary operation
 		switch ($operation) {
 			//	Greater than
 			case '>':
-				$result = ($operand1 > $operand2);
+				if ($useLowercaseFirstComparison) {
+					$result = $this->strcmpLowercaseFirst($operand1, $operand2) > 0;
+				} else {
+					$result = ($operand1 > $operand2);
+				}
 				break;
 			//	Less than
 			case '<':
-				$result = ($operand1 < $operand2);
+				if ($useLowercaseFirstComparison) {
+					$result = $this->strcmpLowercaseFirst($operand1, $operand2) < 0;
+				} else {
+					$result = ($operand1 < $operand2);
+				}
 				break;
 			//	Equality
 			case '=':
@@ -3573,11 +3595,19 @@ class PHPExcel_Calculation {
 				break;
 			//	Greater than or equal
 			case '>=':
-				$result = ($operand1 >= $operand2);
+				if ($useLowercaseFirstComparison) {
+					$result = $this->strcmpLowercaseFirst($operand1, $operand2) >= 0;
+				} else {
+					$result = ($operand1 >= $operand2);
+				}
 				break;
 			//	Less than or equal
 			case '<=':
-				$result = ($operand1 <= $operand2);
+				if ($useLowercaseFirstComparison) {
+					$result = $this->strcmpLowercaseFirst($operand1, $operand2) <= 0;
+				} else {
+					$result = ($operand1 <= $operand2);
+				}
 				break;
 			//	Inequality
 			case '<>':
@@ -3592,6 +3622,21 @@ class PHPExcel_Calculation {
 		return TRUE;
 	}	//	function _executeBinaryComparisonOperation()
 
+	/**
+	 * Compare two strings in the same way as strcmp() except that lowercase come before uppercase letters
+	 * @param string $str1
+	 * @param string $str2
+	 * @return integer
+	 */
+	private function strcmpLowercaseFirst($str1, $str2)
+	{
+		$from = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
+		$to = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+		$inversedStr1 = strtr($str1, $from, $to);
+		$inversedStr2 = strtr($str2, $from, $to);
+
+		return strcmp($inversedStr1, $inversedStr2);
+	}
 
 	private function _executeNumericBinaryOperation($cellID,$operand1,$operand2,$operation,$matrixFunction,&$stack) {
 		//	Validate the two operands
diff --git a/unitTests/Classes/PHPExcel/CalculationTest.php b/unitTests/Classes/PHPExcel/CalculationTest.php
new file mode 100644
index 0000000..8f8ce7e
--- /dev/null
+++ b/unitTests/Classes/PHPExcel/CalculationTest.php
@@ -0,0 +1,35 @@
+<?php
+
+require_once 'testDataFileIterator.php';
+
+class CalculationTest extends PHPUnit_Framework_TestCase
+{
+
+    public function setUp()
+    {
+        if (!defined('PHPEXCEL_ROOT')) {
+            define('PHPEXCEL_ROOT', APPLICATION_PATH . '/');
+        }
+        require_once(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
+    }
+
+    /**
+     * @dataProvider providerBinaryComparisonOperation
+     */
+    public function testBinaryComparisonOperation($formula, $expectedResultExcel, $expectedResultOpenOffice)
+    {
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_EXCEL);
+        $resultExcel = \PHPExcel_Calculation::getInstance()->_calculateFormulaValue($formula);
+        $this->assertEquals($expectedResultExcel, $resultExcel, 'should be Excel compatible');
+
+        PHPExcel_Calculation_Functions::setCompatibilityMode(PHPExcel_Calculation_Functions::COMPATIBILITY_OPENOFFICE);
+        $resultOpenOffice = \PHPExcel_Calculation::getInstance()->_calculateFormulaValue($formula);
+        $this->assertEquals($expectedResultOpenOffice, $resultOpenOffice, 'should be OpenOffice compatible');
+    }
+
+    public function providerBinaryComparisonOperation()
+    {
+        return new testDataFileIterator('rawTestData/CalculationBinaryComparisonOperation.data');
+    }
+
+}
diff --git a/unitTests/rawTestData/CalculationBinaryComparisonOperation.data b/unitTests/rawTestData/CalculationBinaryComparisonOperation.data
new file mode 100644
index 0000000..de04cbf
--- /dev/null
+++ b/unitTests/rawTestData/CalculationBinaryComparisonOperation.data
@@ -0,0 +1,53 @@
+# formula, expectedResultExcel, expectedResultOpenOffice
+'=TRUE',	TRUE,	TRUE
+'=1 + 2.5',	3.5,	3.5
+'=2.5 + 1',	3.5,	3.5
+'=1 - 2.5',	-1.5,	-1.5
+'=2.5 - 1',	1.5,	1.5
+'=3 > 1',	TRUE,	TRUE
+'=3 > 3',	FALSE,	FALSE
+'=1 > 3',	FALSE,	FALSE
+'=3 < 1',	FALSE,	FALSE
+'=3 < 3',	FALSE,	FALSE
+'=1 < 3',	TRUE,	TRUE
+'=3 = 1',	FALSE,	FALSE
+'=3 = 3',	TRUE,	TRUE
+'=1 = 1.0',	TRUE,	TRUE
+'=3 >= 1',	TRUE,	TRUE
+'=3 >= 3',	TRUE,	TRUE
+'=1 >= 3',	FALSE,	FALSE
+'=3 <= 1',	FALSE,	FALSE
+'=3 <= 3',	TRUE,	TRUE
+'=1 <= 3',	TRUE,	TRUE
+'=3 <> 1',	TRUE,	TRUE
+'=3 <> 3',	FALSE,	FALSE
+'=1 <> 1.0',	FALSE,	FALSE
+'="a" > "a"',	FALSE,	FALSE
+'="A" > "A"',	FALSE,	FALSE
+'="A" > "a"',	FALSE,	TRUE
+'="a" > "A"',	FALSE,	FALSE
+'="a" < "a"',	FALSE,	FALSE
+'="A" < "A"',	FALSE,	FALSE
+'="A" < "a"',	FALSE,	FALSE
+'="a" < "A"',	FALSE,	TRUE
+'="a" = "a"',	TRUE,	TRUE
+'="A" = "A"',	TRUE,	TRUE
+'="A" = "a"',	TRUE,	FALSE
+'="a" = "A"',	TRUE,	FALSE
+'="a" <= "a"',	TRUE,	TRUE
+'="A" <= "A"',	TRUE,	TRUE
+'="A" <= "a"',	TRUE,	FALSE
+'="a" <= "A"',	TRUE,	TRUE
+'="a" >= "a"',	TRUE,	TRUE
+'="A" >= "A"',	TRUE,	TRUE
+'="A" >= "a"',	TRUE,	TRUE
+'="a" >= "A"',	TRUE,	FALSE
+'="a" <> "a"',	FALSE,	FALSE
+'="A" <> "A"',	FALSE,	FALSE
+'="A" <> "a"',	FALSE,	TRUE
+'="a" <> "A"',	FALSE,	TRUE
+'="A" > "b"',	FALSE,	TRUE
+'="a" > "b"',	FALSE,	FALSE
+'="b" > "a"',	TRUE,	TRUE
+'="b" > "A"',	TRUE,	FALSE
+'="a2" > "a10"',	TRUE,	TRUE // Test natural sorting is not used