diff --git a/src/exportable/ExportableInvariant.ts b/src/exportable/ExportableInvariant.ts
index ea417149..381e5337 100644
--- a/src/exportable/ExportableInvariant.ts
+++ b/src/exportable/ExportableInvariant.ts
@@ -1,5 +1,7 @@
 import { fshtypes } from 'fsh-sushi';
 import { Exportable, ExportableAssignmentRule, ExportableInsertRule } from '.';
+import { fshifyString } from './common';
+import { EOL } from 'os';
 
 export class ExportableInvariant extends fshtypes.Invariant implements Exportable {
   rules: (ExportableAssignmentRule | ExportableInsertRule)[];
@@ -7,4 +9,28 @@ export class ExportableInvariant extends fshtypes.Invariant implements Exportabl
   constructor(name: string) {
     super(name);
   }
+
+  metadataToFSH(): string {
+    const resultLines: string[] = [];
+    resultLines.push(`Invariant: ${this.name}`);
+    if (this.description) {
+      // Description can be a multiline string.
+      // If it contains newline characters, treat it as a multiline string.
+      if (this.description.indexOf('\n') > -1) {
+        resultLines.push(`Description: """${this.description}"""`);
+      } else {
+        resultLines.push(`Description: "${fshifyString(this.description)}"`);
+      }
+    }
+    if (this.severity) {
+      resultLines.push(`* severity = ${this.severity}`);
+    }
+    if (this.expression) {
+      resultLines.push(`* expression = "${fshifyString(this.expression)}"`);
+    }
+    if (this.xpath) {
+      resultLines.push(`* xpath = "${fshifyString(this.xpath)}"`);
+    }
+    return resultLines.join(EOL);
+  }
 }
diff --git a/test/exportable/ExportableInvariant.test.ts b/test/exportable/ExportableInvariant.test.ts
index 58f519eb..cda75543 100644
--- a/test/exportable/ExportableInvariant.test.ts
+++ b/test/exportable/ExportableInvariant.test.ts
@@ -1,6 +1,6 @@
 import { EOL } from 'os';
 import { fshtypes } from 'fsh-sushi';
-import { ExportableInvariant } from '../../src/exportable';
+import { ExportableAssignmentRule, ExportableInvariant } from '../../src/exportable';
 
 describe('ExportableInvariant', () => {
   it('should export the simplest invariant', () => {
@@ -21,9 +21,9 @@ describe('ExportableInvariant', () => {
     const expectedResult = [
       'Invariant: inv-2',
       'Description: "This is an important condition."',
-      'Severity: #error',
-      'Expression: "requirement.exists()"',
-      'XPath: "f:requirement"'
+      '* severity = #error',
+      '* expression = "requirement.exists()"',
+      '* xpath = "f:requirement"'
     ].join(EOL);
     const result = input.toFSH();
     expect(result).toBe(expectedResult);
@@ -39,9 +39,38 @@ describe('ExportableInvariant', () => {
     const expectedResult = [
       'Invariant: inv-3',
       'Description: """Please do this.\nPlease always do this with a \\ character."""',
-      'Severity: #warning',
-      'Expression: "requirement.contains(\\"\\\\\\")"',
-      'XPath: "f:requirement"'
+      '* severity = #warning',
+      '* expression = "requirement.contains(\\"\\\\\\")"',
+      '* xpath = "f:requirement"'
+    ].join(EOL);
+    const result = input.toFSH();
+    expect(result).toBe(expectedResult);
+  });
+
+  it('should produce FSH for an invariant with additional rules', () => {
+    const input = new ExportableInvariant('inv-4');
+    input.description = 'This is an important condition.';
+    input.severity = new fshtypes.FshCode('error');
+    input.expression = 'requirement.exists()';
+    input.xpath = 'f:requirement';
+
+    const requirements = new ExportableAssignmentRule('requirements');
+    requirements.value = 'This is necessary because it is important.';
+    const extensionUrl = new ExportableAssignmentRule('human.extension[0].url');
+    extensionUrl.value = 'http://example.org/SomeExtension';
+    const extensionValue = new ExportableAssignmentRule('human.extension[0].valueString');
+    extensionValue.value = 'ExtensionValue';
+    input.rules.push(requirements, extensionUrl, extensionValue);
+
+    const expectedResult = [
+      'Invariant: inv-4',
+      'Description: "This is an important condition."',
+      '* severity = #error',
+      '* expression = "requirement.exists()"',
+      '* xpath = "f:requirement"',
+      '* requirements = "This is necessary because it is important."',
+      '* human.extension[0].url = "http://example.org/SomeExtension"',
+      '* human.extension[0].valueString = "ExtensionValue"'
     ].join(EOL);
     const result = input.toFSH();
     expect(result).toBe(expectedResult);