diff --git a/liboctave/numeric/lo-mappers.h b/liboctave/numeric/lo-mappers.h
--- a/liboctave/numeric/lo-mappers.h
+++ b/liboctave/numeric/lo-mappers.h
@@ -471,9 +471,9 @@ OCTAVE_DEPRECATED ("use 'octave::math::a
 inline float arg (float x) { return octave::math::arg (x); }
 
 OCTAVE_DEPRECATED ("use 'octave::math::conj' instead")
-inline double conj (double x) { return octave::math::conj (x); }
+inline double conj (double x) { return x; }
 OCTAVE_DEPRECATED ("use 'octave::math::conj' instead")
-inline float conj (float x) { return octave::math::conj (x); }
+inline float conj (float x) { return x; }
 
 OCTAVE_DEPRECATED ("use 'octave::math::imag' instead")
 inline double imag (double x) { return octave::math::imag (x); }