diff --git a/flang/lib/Optimizer/CodeGen/TypeConverter.h b/flang/lib/Optimizer/CodeGen/TypeConverter.h
--- a/flang/lib/Optimizer/CodeGen/TypeConverter.h
+++ b/flang/lib/Optimizer/CodeGen/TypeConverter.h
@@ -57,6 +57,10 @@
     addConversion(
         [&](fir::CharacterType charTy) { return convertCharType(charTy); });
     addConversion([&](HeapType heap) { return convertPointerLike(heap); });
+    addConversion([&](fir::IntegerType intTy) {
+      return mlir::IntegerType::get(
+          &getContext(), kindMapping.getIntegerBitsize(intTy.getFKind()));
+    });
     addConversion([&](fir::LogicalType boolTy) {
       return mlir::IntegerType::get(
           &getContext(), kindMapping.getLogicalBitsize(boolTy.getFKind()));
diff --git a/flang/test/Fir/types-to-llvm.fir b/flang/test/Fir/types-to-llvm.fir
--- a/flang/test/Fir/types-to-llvm.fir
+++ b/flang/test/Fir/types-to-llvm.fir
@@ -128,6 +128,30 @@
 
 // -----
 
+// Test `!fir.integer<KIND>` conversion.
+
+func private @foo0(%arg0: !fir.int<1>)
+// CHECK-LABEL: foo0
+// CHECK-SAME: i8
+
+func private @foo1(%arg0: !fir.int<2>)
+// CHECK-LABEL: foo1
+// CHECK-SAME: i16
+
+func private @foo2(%arg0: !fir.int<4>)
+// CHECK-LABEL: foo2
+// CHECK-SAME: i32
+
+func private @foo3(%arg0: !fir.int<8>)
+// CHECK-LABEL: foo3
+// CHECK-SAME: i64
+
+func private @foo4(%arg0: !fir.int<16>)
+// CHECK-LABEL: foo4
+// CHECK-SAME: i128
+
+// -----
+
 // Test `!fir.logical<KIND>` conversion.
 
 func private @foo0(%arg0: !fir.logical<1>)