diff --git a/src/subscript/fmuobs/parsers.py b/src/subscript/fmuobs/parsers.py
index 607a9e1ac..50d6253c9 100644
--- a/src/subscript/fmuobs/parsers.py
+++ b/src/subscript/fmuobs/parsers.py
@@ -462,7 +462,11 @@ def resinsight_df2df(ri_dframe: pd.DataFrame) -> pd.DataFrame:
 
     dframe = ri_dframe.copy()
     dframe.rename({"VECTOR": "KEY"}, axis="columns", inplace=True)
-    dframe["LABEL"] = dframe["KEY"].astype(str)  # + "-" + dframe["DATE"].astype(str)
+    dframe["LABEL"] = (
+        dframe["KEY"].astype(str)
+        + "-"
+        + (dframe.groupby("KEY").cumcount() + 1).astype(str)
+    )
     dframe["CLASS"] = "SUMMARY_OBSERVATION"
     if "DATE" in dframe:
         dframe["DATE"] = pd.to_datetime(dframe["DATE"])
diff --git a/tests/testdata_fmuobs/ert-doc.csv b/tests/testdata_fmuobs/ert-doc.csv
index 65c412744..9c2a6fac4 100644
--- a/tests/testdata_fmuobs/ert-doc.csv
+++ b/tests/testdata_fmuobs/ert-doc.csv
@@ -1,5 +1,6 @@
 CLASS,LABEL,VALUE,ERROR,DATE,KEY,RESTART,DAYS,OBS,FIELD,I,J,K,SOURCE,DATA,OBS_FILE,INDEX_LIST,ERROR_MODE,ERROR_MIN,SEGMENT,START,STOP
 SUMMARY_OBSERVATION,SEP_TEST_2005,100.0,5.0,2005-08-21,GOPR:BRENT,,,,,,,,,,,,,,,,
+SUMMARY_OBSERVATION,SEP_TEST_2006,100.0,5.0,2006-08-21,GOPR:BRENT,,,,,,,,,,,,,,,,
 SUMMARY_OBSERVATION,SEP_TEST_RST_2005,100.0,5.0,,GOPR:BRENT,42.0,,,,,,,,,,,,,,,
 SUMMARY_OBSERVATION,SEP_TEST_2008,213.0,10.0,,GOPR:NESS,,911.0,,,,,,,,,,,,,,
 BLOCK_OBSERVATION,RFT_2006,100.0,5.0,2006-10-22,,,,P1,PRESSURE,1.0,1.0,1.0,,,,,,,,,
diff --git a/tests/testdata_fmuobs/ert-doc.obs b/tests/testdata_fmuobs/ert-doc.obs
index 9d517a528..5e20080c0 100644
--- a/tests/testdata_fmuobs/ert-doc.obs
+++ b/tests/testdata_fmuobs/ert-doc.obs
@@ -1,4 +1,4 @@
- -- These observation data are copied from the ERT docs,
+ -- These observation data are mainly copied from the ERT docs,
  -- https://github.com/equinor/ert/blob/master/docs/rst/manual/reference/configuration/observations.rst
 
  SUMMARY_OBSERVATION SEP_TEST_2005
@@ -8,6 +8,14 @@
     DATE  = 21/08/2005;
     KEY   = GOPR:BRENT;
  };
+ -- Duplicate key, but unique label and date.
+ SUMMARY_OBSERVATION SEP_TEST_2006
+ {
+    VALUE = 100.0;
+    ERROR =     5;
+    DATE  = 21/08/2006;
+    KEY   = GOPR:BRENT;
+ };
  
  -- Giving the observation time in terms of restart number.
  SUMMARY_OBSERVATION SEP_TEST_RST_2005
diff --git a/tests/testdata_fmuobs/ert-doc.yml b/tests/testdata_fmuobs/ert-doc.yml
index 152ed3a7a..8201596ef 100644
--- a/tests/testdata_fmuobs/ert-doc.yml
+++ b/tests/testdata_fmuobs/ert-doc.yml
@@ -53,6 +53,10 @@ smry:
     error: 5.0
     label: SEP_TEST_2005
     value: 100.0
+  - date: '2006-08-21'
+    error: 5.0
+    label: SEP_TEST_2006
+    value: 100.0
   - error: 5.0
     label: SEP_TEST_RST_2005
     restart: 42.0
diff --git a/tests/testdata_fmuobs/ri-obs.csv b/tests/testdata_fmuobs/ri-obs.csv
index e3f2c3cb6..5915bdc68 100644
--- a/tests/testdata_fmuobs/ri-obs.csv
+++ b/tests/testdata_fmuobs/ri-obs.csv
@@ -1,2 +1,3 @@
 DATE;VECTOR;VALUE;ERROR
 2005-08-21;GOPR:BRENT;100.0;5.0
+2006-08-21;GOPR:BRENT;100.0;5.0