diff --git a/skimage/viewer/canvastools/recttool.py b/skimage/viewer/canvastools/recttool.py
index 3dcff080..d4ae113e 100644
--- a/skimage/viewer/canvastools/recttool.py
+++ b/skimage/viewer/canvastools/recttool.py
@@ -62,7 +62,7 @@ class RectangleTool(CanvasToolBase, RectangleSelector):
 
         if on_enter is None:
             def on_enter(extents):
-                print "(xmin=%.3g, xmax=%.3g, ymin=%.3g, ymax=%.3g)" % extents
+                print("(xmin=%.3g, xmax=%.3g, ymin=%.3g, ymax=%.3g)" % extents)
         self.callback_on_enter = on_enter
 
         props = dict(mec=props['edgecolor'])
@@ -210,5 +210,5 @@ if __name__ == '__main__':
 
     rect_tool = RectangleTool(ax)
     plt.show()
-    print "Final selection:",
+    print("Final selection:")
     rect_tool.callback_on_enter(rect_tool.extents)
diff --git a/skimage/viewer/plugins/color_histogram.py b/skimage/viewer/plugins/color_histogram.py
index 3c15fbd3..166b2805 100644
--- a/skimage/viewer/plugins/color_histogram.py
+++ b/skimage/viewer/plugins/color_histogram.py
@@ -13,7 +13,7 @@ class ColorHistogram(PlotPlugin):
     def __init__(self, **kwargs):
         super(ColorHistogram, self).__init__(height=400, **kwargs)
 
-        print self.help()
+        print(self.help())
 
     def attach(self, image_viewer):
         super(ColorHistogram, self).attach(image_viewer)
diff --git a/skimage/viewer/plugins/crop.py b/skimage/viewer/plugins/crop.py
index 39e59eb8..61f61034 100644
--- a/skimage/viewer/plugins/crop.py
+++ b/skimage/viewer/plugins/crop.py
@@ -13,7 +13,7 @@ class Crop(Plugin):
         super(Crop, self).__init__(**kwargs)
         self.maxdist = maxdist
         self.add_widget(SaveButtons())
-        print self.help()
+        print(self.help())
 
     def attach(self, image_viewer):
         super(Crop, self).attach(image_viewer)
diff --git a/skimage/viewer/plugins/labelplugin.py b/skimage/viewer/plugins/labelplugin.py
index 8ef02234..d224811c 100644
--- a/skimage/viewer/plugins/labelplugin.py
+++ b/skimage/viewer/plugins/labelplugin.py
@@ -25,7 +25,7 @@ class LabelPainter(Plugin):
         self.add_widget(self._radius_widget)
         self.add_widget(self._label_widget)
 
-        print self.help()
+        print(self.help())
 
     def help(self):
         helpstr = ("Label painter",
diff --git a/skimage/viewer/plugins/lineprofile.py b/skimage/viewer/plugins/lineprofile.py
index 5946b478..c9ceedc5 100644
--- a/skimage/viewer/plugins/lineprofile.py
+++ b/skimage/viewer/plugins/lineprofile.py
@@ -41,7 +41,7 @@ class LineProfile(PlotPlugin):
             maxdist = epsilon
         self.maxdist = maxdist
         self._limit_type = limits
-        print self.help()
+        print(self.help())
 
     def attach(self, image_viewer):
         super(LineProfile, self).attach(image_viewer)
diff --git a/skimage/viewer/plugins/measure.py b/skimage/viewer/plugins/measure.py
index 4911a1ff..71412a3b 100644
--- a/skimage/viewer/plugins/measure.py
+++ b/skimage/viewer/plugins/measure.py
@@ -25,7 +25,7 @@ class Measure(Plugin):
         self.add_widget(self._length)
         self.add_widget(self._angle)
 
-        print self.help()
+        print(self.help())
 
     def attach(self, image_viewer):
         super(Measure, self).attach(image_viewer)