diff --git a/.gitignore b/.gitignore
index 7f2e43bd..eb52d2c0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,4 +41,5 @@ artifacts/*
 *.nuget.targets
 *.lock.json
 *.nuget.props
+*.DotSettings.user
 
diff --git a/src/CommandLine/Core/TypeConverter.cs b/src/CommandLine/Core/TypeConverter.cs
index 2cec8ada..ad2b7d81 100644
--- a/src/CommandLine/Core/TypeConverter.cs
+++ b/src/CommandLine/Core/TypeConverter.cs
@@ -84,7 +84,7 @@ private static Result<object, Exception> ChangeTypeScalarImpl(string value, Type
                     return (value == null) ? empty() : withValue();
                 };
 
-                return value.IsBooleanString()
+                return value.IsBooleanString() && conversionType == typeof(bool)
                     ? value.ToBoolean() : conversionType.GetTypeInfo().IsEnum
                         ? value.ToEnum(conversionType, ignoreValueCase) : safeChangeType();
             };
diff --git a/tests/CommandLine.Tests/CommandLine.Tests.csproj b/tests/CommandLine.Tests/CommandLine.Tests.csproj
index f3c6925b..dfcc5c1e 100644
--- a/tests/CommandLine.Tests/CommandLine.Tests.csproj
+++ b/tests/CommandLine.Tests/CommandLine.Tests.csproj
@@ -112,6 +112,7 @@
       <SubType>Code</SubType>
     </Compile>
     <Compile Include="Unit\Core\TokenTests.cs" />
+    <Compile Include="Unit\Core\TypeConverterTests.cs" />
     <Compile Include="Unit\Infrastructure\FSharpOptionHelperTests.cs" />
     <Compile Include="Unit\Core\ReflectionExtensions.cs" />
     <Compile Include="Unit\ParserResultExtensionsTests.cs" />
diff --git a/tests/CommandLine.Tests/Unit/Core/TypeConverterTests.cs b/tests/CommandLine.Tests/Unit/Core/TypeConverterTests.cs
new file mode 100644
index 00000000..7642a80a
--- /dev/null
+++ b/tests/CommandLine.Tests/Unit/Core/TypeConverterTests.cs
@@ -0,0 +1,111 @@
+using System;
+using System.CodeDom;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using CommandLine.Core;
+using CSharpx;
+using FluentAssertions;
+using Xunit;
+
+namespace CommandLine.Tests.Unit.Core
+{
+    public class TypeConverterTests
+    {
+        enum TestEnum
+        {
+            ValueA = 1,
+            ValueB = 2
+        }
+
+        [Theory]
+        [MemberData("ChangeType_scalars_source")]
+        public void ChangeType_scalars(string testValue, Type destinationType, bool expectFail, object expectedResult)
+        {
+            Maybe<object> result = TypeConverter.ChangeType(new[] {testValue}, destinationType, true, CultureInfo.InvariantCulture, true);
+
+            if (expectFail)
+            {
+                result.MatchNothing().Should().BeTrue("should fail parsing");
+            }
+            else
+            {
+                object matchedValue;
+
+                result.MatchJust(out matchedValue).Should().BeTrue("should parse successfully");
+                Assert.Equal(matchedValue, expectedResult);
+            }
+        }
+
+        public static IEnumerable<object[]> ChangeType_scalars_source
+        {
+            get
+            {
+                return new[]
+                {
+                    new object[] {"1", typeof (int), false, 1},
+                    new object[] {"0", typeof (int), false, 0},
+                    new object[] {"-1", typeof (int), false, -1},
+                    new object[] {"abcd", typeof (int), true, null},
+                    new object[] {"1.0", typeof (int), true, null},
+                    new object[] {int.MaxValue.ToString(), typeof (int), false, int.MaxValue},
+                    new object[] {int.MinValue.ToString(), typeof (int), false, int.MinValue},
+                    new object[] {((long) int.MaxValue + 1).ToString(), typeof (int), true, null},
+                    new object[] {((long) int.MinValue - 1).ToString(), typeof (int), true, null},
+
+                    new object[] {"1", typeof (uint), false, (uint) 1},
+                    new object[] {"0", typeof (uint), false, (uint) 0},
+                    new object[] {"-1", typeof (uint), true, null},
+                    new object[] {uint.MaxValue.ToString(), typeof (uint), false, uint.MaxValue},
+                    new object[] {uint.MinValue.ToString(), typeof (uint), false, uint.MinValue},
+                    new object[] {((long) uint.MaxValue + 1).ToString(), typeof (uint), true, null},
+                    new object[] {((long) uint.MinValue - 1).ToString(), typeof (uint), true, null},
+
+                    new object[] {"true", typeof (bool), false, true},
+                    new object[] {"True", typeof (bool), false, true},
+                    new object[] {"TRUE", typeof (bool), false, true},
+                    new object[] {"false", typeof (bool), false, false},
+                    new object[] {"False", typeof (bool), false, false},
+                    new object[] {"FALSE", typeof (bool), false, false},
+                    new object[] {"abcd", typeof (bool), true, null},
+                    new object[] {"0", typeof (bool), true, null},
+                    new object[] {"1", typeof (bool), true, null},
+
+                    new object[] {"1.0", typeof (float), false, 1.0f},
+                    new object[] {"0.0", typeof (float), false, 0.0f},
+                    new object[] {"-1.0", typeof (float), false, -1.0f},
+                    new object[] {"abcd", typeof (float), true, null},
+
+                    new object[] {"1.0", typeof (double), false, 1.0},
+                    new object[] {"0.0", typeof (double), false, 0.0},
+                    new object[] {"-1.0", typeof (double), false, -1.0},
+                    new object[] {"abcd", typeof (double), true, null},
+
+                    new object[] {"1.0", typeof (decimal), false, 1.0m},
+                    new object[] {"0.0", typeof (decimal), false, 0.0m},
+                    new object[] {"-1.0", typeof (decimal), false, -1.0m},
+                    new object[] {"-1.123456", typeof (decimal), false, -1.123456m},
+                    new object[] {"abcd", typeof (decimal), true, null},
+
+                    new object[] {"", typeof (string), false, ""},
+                    new object[] {"abcd", typeof (string), false, "abcd"},
+
+                    new object[] {"ValueA", typeof (TestEnum), false, TestEnum.ValueA},
+                    new object[] {"VALUEA", typeof (TestEnum), false, TestEnum.ValueA},
+                    new object[] {"ValueB", typeof(TestEnum), false, TestEnum.ValueB},
+                    new object[] {((int) TestEnum.ValueA).ToString(), typeof (TestEnum), false, TestEnum.ValueA},
+                    new object[] {((int) TestEnum.ValueB).ToString(), typeof (TestEnum), false, TestEnum.ValueB},
+                    new object[] {((int) TestEnum.ValueB + 1).ToString(), typeof (TestEnum), true, null},
+                    new object[] {((int) TestEnum.ValueA - 1).ToString(), typeof (TestEnum), true, null},
+
+                    // Failed before #339
+                    new object[] {"false", typeof (int), true, 0},
+                    new object[] {"true", typeof (int), true, 0}
+                };
+            }
+        }
+    }
+}