diff --git a/src/poisson.F90 b/src/poisson.F90
index abfa72693d9189ce1638edd1d2955055c5418f47..fd7f9030f1e7fe37db1b6c53f3fd6e4282e40842 100644
--- a/src/poisson.F90
+++ b/src/poisson.F90
@@ -95,6 +95,7 @@ SUBROUTINE poisson
     END DO
   END DO
 
-!write(*,*) 'gammaD =',gammaD
+! Cancel origin singularity
+phi(ikr_0,ikz_0) = 0
 
 END SUBROUTINE poisson