diff --git a/demo/md-plugins.ts b/demo/md-plugins.ts
index 19e494b1..9dcffb89 100644
--- a/demo/md-plugins.ts
+++ b/demo/md-plugins.ts
@@ -10,6 +10,7 @@ const color = require('markdown-it-color').colorPlugin;
 import math from 'markdown-it-katex';
 
 import meta from '@doc-tools/transform/lib/plugins/meta';
+import checkbox from '@doc-tools/transform/lib/plugins/checkbox';
 import deflist from '@doc-tools/transform/lib/plugins/deflist';
 import anchors from '@doc-tools/transform/lib/plugins/anchors';
 import cut from '@doc-tools/transform/lib/plugins/cut';
@@ -35,6 +36,7 @@ const defaultPlugins: PluginWithParams[] = [
     yfmTable,
     file,
     imsize,
+    checkbox,
 ];
 const extendedPlugins = defaultPlugins.concat(sub, ins, mark, math, color);
 
diff --git a/src/extensions/yfm/Checkbox/Checkbox.test.ts b/src/extensions/yfm/Checkbox/Checkbox.test.ts
index 8d3859bb..feccc9ef 100644
--- a/src/extensions/yfm/Checkbox/Checkbox.test.ts
+++ b/src/extensions/yfm/Checkbox/Checkbox.test.ts
@@ -6,12 +6,17 @@ import {CheckboxNode} from './const';
 import {Checkbox} from './index';
 
 const {schema, parser, serializer} = new ExtensionsManager({
-    extensions: (builder) => builder.use(BaseSchema, {}).use(Checkbox, {}),
+    extensions: (builder) =>
+        builder
+            .use(BaseSchema, {})
+            .use(Checkbox, {checkboxLabelPlaceholder: 'checkbox-placeholder'}),
 }).buildDeps();
 
 const {
     doc,
     checkbox,
+    cbInput,
+    cbLabel,
     checkboxInput0,
     checkboxInput1,
     checkboxInput2,
@@ -22,6 +27,8 @@ const {
     doc: {nodeType: BaseNode.Doc},
     p: {nodeType: BaseNode.Paragraph},
     checkbox: {nodeType: CheckboxNode.Checkbox},
+    cbInput: {nodeType: CheckboxNode.Input},
+    cbLabel: {nodeType: CheckboxNode.Label},
     checkboxInput0: {nodeType: CheckboxNode.Input, id: 'yfm-editor-checkbox0'},
     checkboxInput1: {
         nodeType: CheckboxNode.Input,
@@ -36,6 +43,8 @@ const {
     | 'doc'
     | 'p'
     | 'checkbox'
+    | 'cbInput'
+    | 'cbLabel'
     | 'checkboxInput0'
     | 'checkboxInput1'
     | 'checkboxInput2'
@@ -44,7 +53,7 @@ const {
     | 'checkboxLabel2'
 >;
 
-const {same} = createMarkupChecker({parser, serializer});
+const {same, serialize} = createMarkupChecker({parser, serializer});
 
 describe('Checkbox extension', () => {
     it('should parse unchecked checkbox', () =>
@@ -55,4 +64,15 @@ describe('Checkbox extension', () => {
 
     it('should not escape characters', () =>
         same('[ ] abobo +', doc(checkbox(checkboxInput2(), checkboxLabel2('abobo +')))));
+
+    it('should substitute placeholder when label is empty', () => {
+        serialize(doc(checkbox(cbInput(), cbLabel())), '[ ] checkbox-placeholder');
+    });
+
+    it('should substitute placeholder when label contains only whitespace characters', () => {
+        serialize(
+            doc(checkbox(cbInput(), cbLabel('    \t    \n    '))),
+            '[ ] checkbox-placeholder',
+        );
+    });
 });
diff --git a/src/extensions/yfm/Checkbox/toYfm.ts b/src/extensions/yfm/Checkbox/toYfm.ts
index f8bdec5d..b5a69b4f 100644
--- a/src/extensions/yfm/Checkbox/toYfm.ts
+++ b/src/extensions/yfm/Checkbox/toYfm.ts
@@ -14,7 +14,7 @@ export const toYfm: Record<CheckboxNode, SerializerNodeToken> = {
     },
 
     [CheckboxNode.Label]: (state, node) => {
-        if (!node.content.size) {
+        if (!node.content.size || node.textContent.trim().length === 0) {
             state.write(getPlaceholderContent(node));
             return;
         }