diff --git a/skimage/morphology/misc.py b/skimage/morphology/misc.py
index fe1f27d8..3b20ef88 100644
--- a/skimage/morphology/misc.py
+++ b/skimage/morphology/misc.py
@@ -1,5 +1,6 @@
 import numpy as np
 import functools
+import warnings
 import scipy.ndimage as nd
 from .selem import _default_selem
 
@@ -128,6 +129,10 @@ def remove_small_objects(ar, min_size=64, connectivity=1, in_place=False):
                          "relabeling the input with `scipy.ndimage.label` or "
                          "`skimage.morphology.label`.")
 
+    if len(component_sizes) == 2:
+        warnings.warn("Only one label was provided to `remove_small_objects`. "
+                      "Did you mean to use a boolean array?")
+
     too_small = component_sizes < min_size
     too_small_mask = too_small[ccs]
     out[too_small_mask] = 0