diff --git a/flang/lib/Semantics/check-declarations.cpp b/flang/lib/Semantics/check-declarations.cpp
index b193252442db9..fff0197bf9a82 100644
--- a/flang/lib/Semantics/check-declarations.cpp
+++ b/flang/lib/Semantics/check-declarations.cpp
@@ -1897,6 +1897,13 @@ void CheckHelper::CheckBindC(const Symbol &symbol) {
       }
     }
   }
+  if (const auto *proc{symbol.detailsIf<ProcEntityDetails>()}) {
+    if (!proc->interface().symbol() ||
+        !proc->interface().symbol()->attrs().test(Attr::BIND_C)) {
+      messages_.Say(symbol.name(),
+          "An interface name with BIND attribute must be specified if the BIND attribute is specified in a procedure declaration statement"_err_en_US);
+    }
+  }
 }
 
 bool CheckHelper::CheckDioDummyIsData(
diff --git a/flang/test/Semantics/bind-c03.f90 b/flang/test/Semantics/bind-c03.f90
new file mode 100644
index 0000000000000..03a544b1954d7
--- /dev/null
+++ b/flang/test/Semantics/bind-c03.f90
@@ -0,0 +1,24 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! Check for C1521
+! If proc-language-binding-spec (bind(c)) is specified, the proc-interface
+! shall appear, it shall be an interface-name, and interface-name shall be
+! declared with a proc-language-binding-spec.
+
+module m
+
+  interface
+    subroutine proc1() bind(c)
+    end
+    subroutine proc2()
+    end
+  end interface
+
+  procedure(proc1), bind(c) :: pc1 ! no error
+
+  !ERROR: An interface name with BIND attribute must be specified if the BIND attribute is specified in a procedure declaration statement
+  procedure(proc2), bind(c) :: pc2
+
+  !ERROR: An interface name with BIND attribute must be specified if the BIND attribute is specified in a procedure declaration statement
+  procedure(integer), bind(c) :: pc3
+
+end
diff --git a/flang/test/Semantics/modfile16.f90 b/flang/test/Semantics/modfile16.f90
index 9599f19a6b7e8..2c596fc500814 100644
--- a/flang/test/Semantics/modfile16.f90
+++ b/flang/test/Semantics/modfile16.f90
@@ -6,15 +6,6 @@ module m
   type, bind(c) :: t
     real :: c
   end type
-  real :: d
-  external :: d
-  bind(c, name='dd') :: d
-  real :: e
-  bind(c, name='ee') :: e
-  external :: e
-  bind(c, name='ff') :: f
-  real :: f
-  external :: f
 contains
   subroutine sub() bind(c, name='sub')
   end
@@ -28,9 +19,6 @@ subroutine sub() bind(c, name='sub')
 !  type,bind(c)::t
 !    real(4)::c
 !  end type
-!  procedure(real(4)),bind(c, name="dd")::d
-!  procedure(real(4)),bind(c, name="ee")::e
-!  procedure(real(4)),bind(c, name="ff")::f
 !contains
 !  subroutine sub() bind(c, name="sub")
 !  end
diff --git a/flang/test/Semantics/resolve82.f90 b/flang/test/Semantics/resolve82.f90
index ef216abd23dbc..69cf407884c23 100644
--- a/flang/test/Semantics/resolve82.f90
+++ b/flang/test/Semantics/resolve82.f90
@@ -19,6 +19,7 @@ end function procFunc
   !WARNING: Attribute 'PRIVATE' cannot be used more than once
   procedure(procFunc), private, pointer, private :: proc2
   !WARNING: Attribute 'BIND(C)' cannot be used more than once
+  !ERROR: An interface name with BIND attribute must be specified if the BIND attribute is specified in a procedure declaration statement
   procedure(procFunc), bind(c), pointer, bind(c) :: proc3
   !WARNING: Attribute 'PROTECTED' cannot be used more than once
   procedure(procFunc), protected, pointer, protected :: proc4