diff --git a/flang/lib/Optimizer/Builder/FIRBuilder.cpp b/flang/lib/Optimizer/Builder/FIRBuilder.cpp
--- a/flang/lib/Optimizer/Builder/FIRBuilder.cpp
+++ b/flang/lib/Optimizer/Builder/FIRBuilder.cpp
@@ -344,6 +344,13 @@
     return create<fir::ReboxOp>(loc, toTy, val, mlir::Value{},
                                 /*slice=*/mlir::Value{});
 
+  if (fir::unwrapRefType(fromTy).isa<fir::RecordType>() &&
+      fir::isPolymorphicType(toTy)) {
+    mlir::Value empty;
+    mlir::ValueRange emptyRange;
+    return create<fir::EmboxOp>(loc, toTy, val, empty, empty, emptyRange);
+  }
+
   return createConvert(loc, toTy, val);
 }
 
diff --git a/flang/test/Lower/polymorphic.f90 b/flang/test/Lower/polymorphic.f90
--- a/flang/test/Lower/polymorphic.f90
+++ b/flang/test/Lower/polymorphic.f90
@@ -543,4 +543,19 @@
 ! CHECK: %{{.*}} = fir.call @_FortranAioOutputDescriptor(%{{.*}}, %[[BOX_NONE]]) fastmath<contract> : (!fir.ref<i8>, !fir.box<none>) -> i1
 ! CHECK: fir.freemem %[[TMP]] : !fir.heap<!fir.array<5x5xi32>>
 
+  subroutine pass_class(p)
+    class(p1) :: p
+  end subroutine
+
 end module
+
+program test
+  use polymorphic_test
+  type(p1) :: a = p1(1,2)
+  call pass_class(a)
+end program
+
+! CHECK-LABEL: func.func @_QQmain() {
+! CHECK: %[[ADDR:.*]] = fir.address_of(@_QFEa) : !fir.ref<!fir.type<_QMpolymorphic_testTp1{a:i32,b:i32}>>
+! CHECK: %[[CLASS:.*]] = fir.embox %[[ADDR]] : (!fir.ref<!fir.type<_QMpolymorphic_testTp1{a:i32,b:i32}>>) -> !fir.class<!fir.type<_QMpolymorphic_testTp1{a:i32,b:i32}>>
+! CHECK: fir.call @_QMpolymorphic_testPpass_class(%[[CLASS]]) {{.*}} : (!fir.class<!fir.type<_QMpolymorphic_testTp1{a:i32,b:i32}>>) -> ()