diff --git a/contrib/distro-tools/build_nwchem b/contrib/distro-tools/build_nwchem
index aeb1d87e0e..c7df775d76 100755
--- a/contrib/distro-tools/build_nwchem
+++ b/contrib/distro-tools/build_nwchem
@@ -1174,9 +1174,26 @@ if [ ${#NWCHEM_OS} -eq 0 ] ; then
   if [ ${#NWCHEM_OS} -ne 0 ] ; then
     if [ ${NWCHEM_OS} == "DARWIN" ] ; then
       export NWCHEM_OS=MACX
-    fi
-    if [ ${NWCHEM_OS} == "AIX" ] ; then
+    elif [ ${NWCHEM_OS} == "AIX" ] ; then
       export NWCHEM_OS=IBM
+    elif [ `expr match ${NWCHEM_OS} CYGWIN` != "0" ] ; then
+      export NWCHEM_OS=CYGWIN
+      if [ ${#NWCHEM_TARGET} -eq 0 ] ; then
+        # There is no CYGWIN64 target so set NWCHEM_TARGET here
+        export NWCHEM_TARGET=${NWCHEM_OS}
+      fi
+    elif [ `expr match ${NWCHEM_OS} CYGNUS` != "0" ] ; then
+      export NWCHEM_OS=CYGNUS
+      if [ ${#NWCHEM_TARGET} -eq 0 ] ; then
+        # There is no CYGNUS64 target so set NWCHEM_TARGET here
+        export NWCHEM_TARGET=${NWCHEM_OS}
+      fi
+    elif [ `expr match ${NWCHEM_OS} INTERIX` != "0" ] ; then
+      export NWCHEM_OS=INTERIX
+      if [ ${#NWCHEM_TARGET} -eq 0 ] ; then
+        # There is no INTERIX64 target so set NWCHEM_TARGET here
+        export NWCHEM_TARGET=${NWCHEM_OS}
+      fi
     fi
   fi
 fi
diff --git a/contrib/distro-tools/build_nwchem_src_distro b/contrib/distro-tools/build_nwchem_src_distro
index 62be6a7d8f..862223a306 100755
--- a/contrib/distro-tools/build_nwchem_src_distro
+++ b/contrib/distro-tools/build_nwchem_src_distro
@@ -29,7 +29,25 @@ if [ -d ${target} ] ; then
 fi
 cp -a ${source} ${target}
 export NWCHEM_TOP=${target}
-export NWCHEM_TARGET=LINUX64
+if [ ${#NWCHEM_TARGET} -eq 0 ] ; then
+  NWCHEM_OS=`uname | tr '[a-z]' '[A-Z]'`
+  if [ $? -ne 0 ] ; then
+    unset NWCHEM_OS
+  fi
+  if [ ${#NWCHEM_OS} -ne 0 ] ; then
+    if [ ${NWCHEM_OS} == "DARWIN" ] ; then
+      export NWCHEM_TARGET=MACX64
+    elif [ `expr match ${NWCHEM_OS} CYGWIN` != "0" ] ; then
+      export NWCHEM_TARGET=CYGWIN
+    elif [ `expr match ${NWCHEM_OS} CYGNUS` != "0" ] ; then
+      export NWCHEM_TARGET=CYGNUS
+    elif [ `expr match ${NWCHEM_OS} INTERIX` != "0" ] ; then
+      export NWCHEM_TARGET=INTERIX
+    else
+      export NWCHEM_TARGET=LINUX64
+    fi
+  fi
+fi
 #
 # Make sure we include the Global Arrays
 #