diff --git a/src/main/java/jnr/ffi/Struct.java b/src/main/java/jnr/ffi/Struct.java
index f235472cb..9bc60a563 100755
--- a/src/main/java/jnr/ffi/Struct.java
+++ b/src/main/java/jnr/ffi/Struct.java
@@ -2183,7 +2183,8 @@ public void set(java.lang.Number value) {
          */
         @Override
         public final int intValue() {
-            return getMemory().getByte(offset());
+            short value = getMemory().getByte(offset());
+            return value < 0 ? (short) ((value & 0x7F) + 0x80) : value;
         }
     }
 
@@ -2202,7 +2203,8 @@ public void set(java.lang.Number value) {
         }
         @Override
         public final int intValue() {
-            return getMemory().getShort(offset());
+            int value = getMemory().getShort(offset());
+            return value < 0 ? (value & 0x7FFF) + 0x8000 : value;
         }
     }
 
@@ -2211,7 +2213,7 @@ public Enum32(Class<E> enumClass) {
             super(NativeType.SINT, enumClass);
         }
         public final E get() {
-            return enumClass.cast(EnumMapper.getInstance(enumClass).valueOf(intValue()));
+            return enumClass.cast(EnumMapper.getInstance(enumClass).valueOf(longValue()));
         }
         public final void set(E value) {
             getMemory().putInt(offset(), EnumMapper.getInstance(enumClass).intValue(value));
@@ -2221,7 +2223,13 @@ public void set(java.lang.Number value) {
         }
         @Override
         public final int intValue() {
-            return getMemory().getInt(offset());
+            return (int) longValue();
+        }
+
+        @Override
+        public long longValue() {
+            long value = getMemory().getInt(offset());
+            return value < 0 ? (long)((value & 0x7FFFFFFFL) + 0x80000000L) : value;
         }
     }
 
@@ -2230,10 +2238,10 @@ public Enum64(Class<E> enumClass) {
             super(NativeType.SLONGLONG, enumClass);
         }
         public final E get() {
-            return enumClass.cast(EnumMapper.getInstance(enumClass).valueOf(intValue()));
+            return enumClass.cast(EnumMapper.getInstance(enumClass).valueOf(longValue()));
         }
         public final void set(E value) {
-            getMemory().putLongLong(offset(), EnumMapper.getInstance(enumClass).intValue(value));
+            getMemory().putLongLong(offset(), EnumMapper.getInstance(enumClass).longValue(value));
         }
         public void set(java.lang.Number value) {
             getMemory().putLongLong(offset(), value.longValue());
@@ -2254,10 +2262,10 @@ public EnumLong(Class<E> enumClass) {
         }
 
         public final E get() {
-            return enumClass.cast(EnumMapper.getInstance(enumClass).valueOf(intValue()));
+            return enumClass.cast(EnumMapper.getInstance(enumClass).valueOf(longValue()));
         }
         public final void set(E value) {
-            getMemory().putNativeLong(offset(), EnumMapper.getInstance(enumClass).intValue(value));
+            set(EnumMapper.getInstance(enumClass).longValue(value));
         }
         public void set(java.lang.Number value) {
             getMemory().putNativeLong(offset(), value.longValue());
diff --git a/src/test/java/jnr/ffi/struct/EnumTest.java b/src/test/java/jnr/ffi/struct/EnumTest.java
index a361bd96d..ef0b182e6 100644
--- a/src/test/java/jnr/ffi/struct/EnumTest.java
+++ b/src/test/java/jnr/ffi/struct/EnumTest.java
@@ -41,6 +41,61 @@ public enum TestEnum {
         B,
         MAGIC
     }
+
+    public enum ByteNegativeEnum
+            implements EnumMapper.IntegerEnum {
+        NEGATIVE(0xF0);
+
+        final int value;
+
+        ByteNegativeEnum(int value) {this.value = value;}
+
+        @Override
+        public int intValue() {
+            return value;
+        }
+    }
+
+    public enum ShortNegativeEnum
+            implements EnumMapper.IntegerEnum {
+        NEGATIVE(0xF000);
+
+        final int value;
+
+        ShortNegativeEnum(int value) {this.value = value;}
+
+        @Override
+        public int intValue() {
+            return value;
+        }
+    }
+
+    public enum IntNegativeEnum {
+        NEGATIVE(0xF00000L);
+
+        final long value;
+
+        IntNegativeEnum(long value) {this.value = value;}
+
+        public long longValue() {
+            return value;
+        }
+    }
+
+    public enum LongEnum {
+        BIGGER_THAN_INT(0xFF00000000000000L);
+
+        private final long value;
+
+        LongEnum(long value) {
+            this.value = value;
+        }
+
+        public long longValue() {
+            return value;
+        }
+    }
+
     public class struct1 extends Struct {
         public final Enum8<TestEnum> b = new Enum8<TestEnum>(TestEnum.class);
         public final Enum16<TestEnum> s = new Enum16<TestEnum>(TestEnum.class);
@@ -130,6 +185,36 @@ public LongAlign() {
         }
 
     }
+    public static class Enum8FieldStruct extends Struct {
+        public final Enum8<ByteNegativeEnum> value = new Enum8<ByteNegativeEnum>(ByteNegativeEnum.class);
+        public Enum8FieldStruct() {
+            super(runtime);
+        }
+    }
+    public static class Enum16FieldStruct extends Struct {
+        public final Enum16<ShortNegativeEnum> value = new Enum16<ShortNegativeEnum>(ShortNegativeEnum.class);
+        public Enum16FieldStruct() {
+            super(runtime);
+        }
+    }
+    public static class Enum32FieldStruct extends Struct {
+        public final Enum32<IntNegativeEnum> value = new Enum32<IntNegativeEnum>(IntNegativeEnum.class);
+        public Enum32FieldStruct() {
+            super(runtime);
+        }
+    }
+    public static class Enum64FieldStruct extends Struct {
+        public final Enum64<LongEnum> value = new Enum64<LongEnum>(LongEnum.class);
+        public Enum64FieldStruct() {
+            super(runtime);
+        }
+    }
+    public static class EnumLongFieldStruct extends Struct {
+        public final EnumLong<LongEnum> value = new EnumLong<LongEnum>(LongEnum.class);
+        public EnumLongFieldStruct() {
+            super(runtime);
+        }
+    }
     @Test public void testInt8InitialValue() {
         struct1 s = new struct1();
         assertEquals("default value not zero", TestEnum.ZERO, s.b.get());
@@ -212,4 +297,43 @@ public void alignSignedLongField() {
         
         assertEquals("native long field not aligned", MAGIC, testlib.struct_align_SignedLong(s));
     }
+
+    @Test
+    public void byteEnumFieldWithNegativeValue()
+    {
+        Enum8FieldStruct struct = new Enum8FieldStruct();
+        struct.value.set(ByteNegativeEnum.NEGATIVE);
+        assertEquals("negative Enum8 value conversation failed", ByteNegativeEnum.NEGATIVE, struct.value.get());
+    }
+
+    @Test
+    public void shortEnumFieldWithNegativeValue()
+    {
+        Enum16FieldStruct struct = new Enum16FieldStruct();
+        struct.value.set(ShortNegativeEnum.NEGATIVE);
+        assertEquals("negative Enum16 value conversation failed", ShortNegativeEnum.NEGATIVE, struct.value.get());
+    }
+
+    @Test
+    public void intEnumFieldWithNegativeValue()
+    {
+        Enum32FieldStruct struct = new Enum32FieldStruct();
+        struct.value.set(IntNegativeEnum.NEGATIVE);
+        assertEquals("negative Enum32 value conversation failed", IntNegativeEnum.NEGATIVE, struct.value.get());
+    }
+
+    @Test
+    public void longLongEnumField(){
+        Enum64FieldStruct struct = new Enum64FieldStruct();
+        struct.value.set(LongEnum.BIGGER_THAN_INT);
+        assertEquals("long Enum64 value conversation failed", LongEnum.BIGGER_THAN_INT, struct.value.get());
+    }
+    @Test
+    public void longEnumFieldX64(){
+        if (runtime.longSize() == 8) {
+            EnumLongFieldStruct struct = new EnumLongFieldStruct();
+            struct.value.set(LongEnum.BIGGER_THAN_INT);
+            assertEquals("long EnumLong value conversation failed", LongEnum.BIGGER_THAN_INT, struct.value.get());
+        }
+    }
 }