diff --git a/.github/workflows/developer.yml b/.github/workflows/developer.yml
index 4e51f579..79ba9a6c 100644
--- a/.github/workflows/developer.yml
+++ b/.github/workflows/developer.yml
@@ -105,7 +105,7 @@ jobs:
         export CFLAGS='-Wall -g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0'        
         export FCFLAGS='-Wall -g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0'        
         export FFLAGS='-Wall -g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0'        
-        cmake .. -DFTP_TEST_FILES=ON -DTEST_FILE_DIR=/home/runner/data
+        cmake .. -DFTP_TEST_FILES=ON -DFTP_LARGE_TEST_FILES=ON -DTEST_FILE_DIR=/home/runner/data
         make VERBOSE=1
         ctest --verbose --output-on-failure --rerun-failed
         gcovr --root .. -v  --html-details --exclude ../tests --exclude CMakeFiles --print-summary -o test-coverage.html &> /dev/null
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 378fbc5b..62f35f6e 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -90,5 +90,11 @@ copy_test_data(ref_WW3_Regional_US_West_Coast_20220718_0000.grib2.inv)
 shell_test(run_wgrib2_tests)
 
 if (FTP_TEST_FILES)
+  copy_test_data(ref_WW3_Regional_US_West_Coast_20220718_0000.grib2.inv)
   shell_test(run_wgrib2_ftp_tests)
-endif()
\ No newline at end of file
+endif()
+
+if (FTP_LARGE_TEST_FILES)
+  copy_test_data(ref_rrfs.t18z.prslev.f000.grib2.inv)
+  shell_test(run_wgrib2_large_ftp_tests)
+endif()
diff --git a/tests/run_wgrib2_ftp_large_tests.sh b/tests/run_wgrib2_ftp_large_tests.sh
new file mode 100755
index 00000000..c6896401
--- /dev/null
+++ b/tests/run_wgrib2_ftp_large_tests.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+# This is an optional test script for the wgrib2 project. 
+# Requires FTP_LARGE_TEST_FILES=ON
+#
+# Alyson Stahl, 4/17/24
+
+set -e
+echo ""
+echo "*** Running wgrib2 tests on large FTP test files"
+
+echo "*** Running an inventory test on a large FTP test file"
+../wgrib2/wgrib2 data/rrfs.t18z.prslev.f000.grib2 > ftp_inv2.txt
+cat ftp_inv2.txt
+cmp ftp_inv2.txt data/ref_rrfs.t18z.prslev.f000.grib2.inv
+
+echo "*** SUCCESS!"
+exit 0
+
diff --git a/tests/run_wgrib2_ftp_tests.sh b/tests/run_wgrib2_ftp_tests.sh
index c122e52f..d55c52cf 100644
--- a/tests/run_wgrib2_ftp_tests.sh
+++ b/tests/run_wgrib2_ftp_tests.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 # This is an optional test script for the wgrib2 project.
+# Requires FTP_TEST_FILES=ON
 #
 # Alyson Stahl, 4/17/24
 
@@ -7,15 +8,11 @@ set -e
 echo ""
 echo "*** Running wgrib2 tests on FTP test files"
 
-# Run an inventory on test files.
+echo "*** Running an inventory test with FTP test file"
 ../wgrib2/wgrib2 data/WW3_Regional_US_West_Coast_20220718_0000.grib2 > ftp_inv1.txt
 cat ftp_inv1.txt
 cmp ftp_inv1.txt data/ref_WW3_Regional_US_West_Coast_20220718_0000.grib2.inv
 
-#../wgrib2/wgrib2 data/rrfs.t18z.prslev.f000.grib2 > ftp_inv2.txt
-#cat ftp_inv2.txt
-#cmp ftp_inv2.txt data/ref_rrfs.t18z.prslev.f000.grib2.inv
-
 echo "*** SUCCESS!"
 exit 0