diff --git a/Source/portable/IAR/AtmelSAM7S64/portmacro.h b/Source/portable/IAR/AtmelSAM7S64/portmacro.h
index 06da3cb67..f31f3c715 100644
--- a/Source/portable/IAR/AtmelSAM7S64/portmacro.h
+++ b/Source/portable/IAR/AtmelSAM7S64/portmacro.h
@@ -86,7 +86,7 @@ extern "C" {
 /* Hardware specifics. */
 #define portSTACK_GROWTH			( -1 )
 #define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )		
-#define portBYTE_ALIGNMENT			4
+#define portBYTE_ALIGNMENT			8
 #define portYIELD()					asm ( "SWI 0" )
 #define portNOP()					asm ( "NOP" )
 /*-----------------------------------------------------------*/	
diff --git a/Source/portable/IAR/LPC2000/portmacro.h b/Source/portable/IAR/LPC2000/portmacro.h
index 14e9a22fd..a42e65a4b 100644
--- a/Source/portable/IAR/LPC2000/portmacro.h
+++ b/Source/portable/IAR/LPC2000/portmacro.h
@@ -88,7 +88,7 @@ extern "C" {
 /* Hardware specifics. */
 #define portSTACK_GROWTH			( -1 )
 #define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )		
-#define portBYTE_ALIGNMENT			4
+#define portBYTE_ALIGNMENT			8
 #define portYIELD()					asm ( "SWI 0" )
 #define portNOP()					asm ( "NOP" )
 /*-----------------------------------------------------------*/	
diff --git a/Source/portable/IAR/STR71x/portmacro.h b/Source/portable/IAR/STR71x/portmacro.h
index d04848938..1bba80dee 100644
--- a/Source/portable/IAR/STR71x/portmacro.h
+++ b/Source/portable/IAR/STR71x/portmacro.h
@@ -89,7 +89,7 @@ extern "C" {
 /* Hardware specifics. */
 #define portSTACK_GROWTH			( -1 )
 #define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )		
-#define portBYTE_ALIGNMENT			4
+#define portBYTE_ALIGNMENT			8
 #define portYIELD()					asm ( "SWI 0" )
 #define portNOP()					asm ( "NOP" )
 /*-----------------------------------------------------------*/	
diff --git a/Source/portable/IAR/STR75x/portmacro.h b/Source/portable/IAR/STR75x/portmacro.h
index 17a59566f..0f5e345a0 100644
--- a/Source/portable/IAR/STR75x/portmacro.h
+++ b/Source/portable/IAR/STR75x/portmacro.h
@@ -88,7 +88,7 @@ extern "C" {
 /* Hardware specifics. */
 #define portSTACK_GROWTH			( -1 )
 #define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )		
-#define portBYTE_ALIGNMENT			4
+#define portBYTE_ALIGNMENT			8
 #define portYIELD()					asm ( "SWI 0" )
 #define portNOP()					asm ( "NOP" )
 /*-----------------------------------------------------------*/	
diff --git a/Source/portable/IAR/STR91x/portmacro.h b/Source/portable/IAR/STR91x/portmacro.h
index f1627a0c2..ae67af865 100644
--- a/Source/portable/IAR/STR91x/portmacro.h
+++ b/Source/portable/IAR/STR91x/portmacro.h
@@ -88,7 +88,7 @@ extern "C" {
 /* Hardware specifics. */
 #define portSTACK_GROWTH			( -1 )
 #define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )
-#define portBYTE_ALIGNMENT			4
+#define portBYTE_ALIGNMENT			8
 #define portYIELD()					asm ( "SWI 0" )
 #define portNOP()					asm ( "NOP" )
 /*-----------------------------------------------------------*/