diff --git a/tsfresh/feature_extraction/extraction.py b/tsfresh/feature_extraction/extraction.py
index d7f33787d..32575dcee 100644
--- a/tsfresh/feature_extraction/extraction.py
+++ b/tsfresh/feature_extraction/extraction.py
@@ -107,7 +107,8 @@ def extract_features(timeseries_container, default_fc_parameters=None,
     :param disable_progressbar: Do not show a progressbar while doing the calculation.
     :type disable_progressbar: bool
 
-    :param impute_function: None, if no imputing should happen or the function to call for imputing.
+    :param impute_function: None, if no imputing should happen or the function to call for imputing the result dataframe.
+        Imputing will never happen on the input data.
     :type impute_function: None or callable
 
     :param profile: Turn on profiling during feature extraction
diff --git a/tsfresh/transformers/feature_augmenter.py b/tsfresh/transformers/feature_augmenter.py
index 85262dbf6..4515e8150 100644
--- a/tsfresh/transformers/feature_augmenter.py
+++ b/tsfresh/transformers/feature_augmenter.py
@@ -112,7 +112,8 @@ def __init__(self, default_fc_parameters=None,
         :param disable_progressbar: Do not show a progressbar while doing the calculation.
         :type disable_progressbar: bool
 
-        :param impute_function: None, if no imputing should happen or the function to call for imputing.
+        :param impute_function: None, if no imputing should happen or the function to call for imputing the result dataframe.
+            Imputing will never happen on the input data.
         :type impute_function: None or function
 
         :param profile: Turn on profiling during feature extraction