diff --git a/loopy/loop.py b/loopy/loop.py
index 66d413987466e98e5a188df93cad49f5584cd3f7..a2793c196991f24aff7e007ec8cb930e171dfa74 100644
--- a/loopy/loop.py
+++ b/loopy/loop.py
@@ -32,7 +32,8 @@ def potential_loop_nest_map(kernel):
     """Returns a dictionary mapping inames to other inames that *could*
     be nested around them.
 
-    :seealso: :func:`loopy.schedule.loop_nest_map`
+    * :seealso: :func:`loopy.schedule.loop_nest_map`
+    * :seealso: :func:`loopy.schedule.find_loop_nest_around_map`
     """
 
     result = {}
@@ -65,6 +66,8 @@ def fuse_loop_domains(kernel):
         parents_per_domain = kernel.parents_per_domain()
         all_parents_per_domain = kernel.all_parents_per_domain()
 
+        iname_to_insns = kernel.iname_to_insns()
+
         new_domains = None
 
         for inner_iname, outer_inames in six.iteritems(lnm):
@@ -77,6 +80,12 @@ def fuse_loop_domains(kernel):
                 if inner_domain_idx == outer_domain_idx:
                     break
 
+                if iname_to_insns[inner_iname] != iname_to_insns[outer_iname]:
+                    # The two inames are imperfectly nested. Domain fusion
+                    # might be invalid when the inner loop is empty, leading to
+                    # the outer loop also being empty.
+                    continue
+
                 if (
                         outer_domain_idx in all_parents_per_domain[inner_domain_idx]
                         and not
diff --git a/test/test_fortran.py b/test/test_fortran.py
index 496b470dea2131890e1c4d113226875a8f8b74a9..902c2d1b7aa0b9436ed51e01dc687837edf8f4ba 100644
--- a/test/test_fortran.py
+++ b/test/test_fortran.py
@@ -517,12 +517,32 @@ def test_fortran_subroutines(ctx_factory):
 
           call twice(n, a(1:n, i))
           call twice(n, a(i, 1:n))
+        end subroutine
+        """
+    prg = lp.parse_fortran(fortran_src)
+    print(lp.generate_code_v2(prg).device_code())
 
 
+def test_domain_fusion_imperfectly_nested():
+    fortran_src = """
+        subroutine imperfect(n, m, a, b)
+            implicit none
+            integer i, j, n, m
+            real a(n), b(n,n)
+
+            do i=1, n
+                a(i) = i
+                do j=1, m
+                    b(i,j) = i*j
+                end do
+            end do
         end subroutine
         """
+
     prg = lp.parse_fortran(fortran_src)
-    print(lp.generate_code_v2(prg).device_code())
+    # If n > 0 and m == 0, a single domain would be empty,
+    # leading (incorrectly) to no assignments to 'a'.
+    assert len(prg["imperfect"].subkernel.domains) > 1
 
 
 if __name__ == "__main__":