diff --git a/CMakeLists.txt b/CMakeLists.txt
index dcafb1fd2..887adc4cf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,6 +57,7 @@ check_c_source_compiles(
       int main(int argc, char *argv[]){return 0;}
       " ECCODES_HAVE_C_INLINE )
 
+include(eccodes_test_endiness)
 
 ###############################################################################
 # some variables/options of this project
@@ -218,8 +219,8 @@ else()
     set( GRIB_TIMER 0 )
 endif()
 
-set( IS_BIG_ENDIAN 0 )
-if( EC_BIG_ENDIAN )
+set( IS_BIG _ENDIAN 0 )
+if( ECCODES_BIG_ENDIAN )
     set( IS_BIG_ENDIAN 1 )
 endif()
 
diff --git a/cmake/eccodes_test_endiness.cmake b/cmake/eccodes_test_endiness.cmake
new file mode 100644
index 000000000..8691c5966
--- /dev/null
+++ b/cmake/eccodes_test_endiness.cmake
@@ -0,0 +1,93 @@
+# (C) Copyright 2011- ECMWF.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation nor
+# does it submit to any jurisdiction.
+
+test_big_endian( _BIG_ENDIAN )
+
+if( _BIG_ENDIAN )
+        set( ECCODES_BIG_ENDIAN    1 )
+        set( ECCODES_LITTLE_ENDIAN 0 )
+else()
+        set( ECCODES_BIG_ENDIAN    0 )
+        set( ECCODES_LITTLE_ENDIAN 1 )
+endif()
+
+set( ECCODES_BIG_ENDIAN    ${ECCODES_BIG_ENDIAN}    PARENT_SCOPE )
+set( ECCODES_LITTLE_ENDIAN ${ECCODES_LITTLE_ENDIAN} PARENT_SCOPE )
+
+if( NOT DEFINED IEEE_BE )
+    check_c_source_runs(
+       "int compare(unsigned char* a,unsigned char* b) {
+         while(*a != 0) if (*(b++)!=*(a++)) return 1;
+         return 0;
+       }
+       int main(int argc,char** argv) {
+         unsigned char dc[]={0x30,0x61,0xDE,0x80,0x93,0x67,0xCC,0xD9,0};
+         double da=1.23456789e-75;
+         unsigned char* ca;
+
+         unsigned char fc[]={0x05,0x83,0x48,0x22,0};
+         float fa=1.23456789e-35;
+
+         if (sizeof(double)!=8) return 1;
+
+         ca=(unsigned char*)&da;
+         if (compare(dc,ca)) return 1;
+
+         if (sizeof(float)!=4) return 1;
+
+         ca=(unsigned char*)&fa;
+         if (compare(fc,ca)) return 1;
+
+         return 0;
+       }" IEEE_BE )
+
+    if( "${IEEE_BE}" STREQUAL "" )
+      set( IEEE_BE 0 CACHE INTERNAL "Test IEEE_BE")
+    endif()
+
+endif()
+
+if( ECCODES_BIG_ENDIAN AND NOT IEEE_BE )
+    ecbuild_critical("Failed to sanity check on endiness: OS should be Big-Endian but compiled code runs differently -- to ignore this pass -DIEEE_BE=0 to CMake/ecBuild")
+endif()
+
+if( NOT DEFINED IEEE_LE )
+    check_c_source_runs(
+       "int compare(unsigned char* a,unsigned char* b) {
+         while(*a != 0) if (*(b++)!=*(a++)) return 1;
+         return 0;
+       }
+       int main(int argc,char** argv) {
+         unsigned char dc[]={0xD9,0xCC,0x67,0x93,0x80,0xDE,0x61,0x30,0};
+         double da=1.23456789e-75;
+         unsigned char* ca;
+
+         unsigned char fc[]={0x22,0x48,0x83,0x05,0};
+         float fa=1.23456789e-35;
+
+         if (sizeof(double)!=8) return 1;
+
+         ca=(unsigned char*)&da;
+         if (compare(dc,ca)) return 1;
+
+         if (sizeof(float)!=4) return 1;
+
+         ca=(unsigned char*)&fa;
+         if (compare(fc,ca)) return 1;
+
+         return 0;
+       }" IEEE_LE )
+
+    if( "${IEEE_LE}" STREQUAL "" )
+      set( IEEE_LE 0 CACHE INTERNAL "Test IEEE_LE")
+    endif()
+endif()
+
+if( ECCODES_LITTLE_ENDIAN AND NOT IEEE_LE )
+    ecbuild_critical("Failed to sanity check on endiness: OS should be Little-Endian but compiled code runs differently -- to ignore this pass -DIEEE_LE=0 to CMake/ecBuild")
+endif()