diff --git a/poisson2d/f90/main.f90 b/poisson2d/f90/main.f90
index 8b3b82f957f7baa152a4c7bc070d3408658f20e6..af3d1e1b818be2e491ce2871ab50fbcbea1cbe54 100644
--- a/poisson2d/f90/main.f90
+++ b/poisson2d/f90/main.f90
@@ -39,6 +39,9 @@ program poisson2d
     real(kind=8)                                :: x
     real(kind=8)                                :: y
 
+    integer                                     :: ix
+    integer                                     :: iy
+
     ! Allocate memory
     allocate(v(NX, NY), f(NX, NY))
 
diff --git a/poisson2d/f90/solver.f90 b/poisson2d/f90/solver.f90
index 6c25bdae9699efb817e5bf2fc7597be4bb2e1b5d..46682f1315fd168674c84a9968c488144a9c54d9 100644
--- a/poisson2d/f90/solver.f90
+++ b/poisson2d/f90/solver.f90
@@ -44,6 +44,10 @@ subroutine solver(v, f, nx, ny, eps, nmax)
     real(kind=8)                                    :: d
     real(kind=8), dimension(:,:), allocatable       :: vp
 
+    integer                                         :: ix
+    integer                                         :: iy
+    integer                                         :: ifail
+
     n = 0
     e = 2.0 * eps