diff --git a/definitions/grib2/section.1.def b/definitions/grib2/section.1.def
index b19eb67f8..af38f69bb 100644
--- a/definitions/grib2/section.1.def
+++ b/definitions/grib2/section.1.def
@@ -95,6 +95,7 @@ concept stepType {
     "sum"     = {selectStepTemplateInterval=1; stepTypeInternal="sum";}
     "severity" = {selectStepTemplateInterval=1; stepTypeInternal="severity";}
     "mode"    = {selectStepTemplateInterval=1; stepTypeInternal="mode";}
+    "index"   = {selectStepTemplateInterval=1; stepTypeInternal="index";}
 }
 
 # 0=atmospheric chemical constituents
diff --git a/definitions/grib2/templates/template.4.statistical.def b/definitions/grib2/templates/template.4.statistical.def
index fde76eba3..ee458ecbf 100644
--- a/definitions/grib2/templates/template.4.statistical.def
+++ b/definitions/grib2/templates/template.4.statistical.def
@@ -69,6 +69,7 @@ if (numberOfTimeRanges == 1 || numberOfTimeRanges == 2) {
     "sum"     = {typeOfStatisticalProcessing=11;}
     "severity" = {typeOfStatisticalProcessing=100;}
     "mode"     = {typeOfStatisticalProcessing=101;}
+    "index"    = {typeOfStatisticalProcessing=102;}
   }
   meta startStep step_in_units(forecastTime,indicatorOfUnitOfTimeRange,stepUnits,
     indicatorOfUnitForTimeRange,lengthOfTimeRange) : no_copy;
diff --git a/tests/grib_step.sh b/tests/grib_step.sh
index 9fc7f9abe..274f1f7ab 100755
--- a/tests/grib_step.sh
+++ b/tests/grib_step.sh
@@ -118,6 +118,12 @@ grib_check_key_equals $temp productDefinitionTemplateNumber,typeOfStatisticalPro
 ${tools_dir}/grib_set -s stepType=mode,paramId=260320     $grib2_sample $temp
 grib_check_key_equals $temp productDefinitionTemplateNumber,typeOfStatisticalProcessing '8 101'
 
+# ECC-1991: stepType for index processing
+# -----------------------------------------
+${tools_dir}/grib_set -s stepType=index $grib2_sample $temp
+grib_check_key_equals $temp productDefinitionTemplateNumber,typeOfStatisticalProcessing '8 102'
+
+
 # ECC-1577: stepType when typeOfTimeIncrement=255
 # -----------------------------------------------
 ${tools_dir}/grib_set -s stepType=accum,typeOfTimeIncrement=255 $grib2_sample $temp