diff --git a/src/supported-value.js b/src/supported-value.js
index 53316dc..e860432 100644
--- a/src/supported-value.js
+++ b/src/supported-value.js
@@ -24,6 +24,7 @@ let el
 function prefixTransitionCallback(match, p1, p2) {
   if (p1 === 'var') return 'var'
   if (p1 === 'all') return 'all'
+  if (p2 === 'var') return ', var'
   if (p2 === 'all') return ', all'
   const prefixedValue = p1 ? supportedProperty(p1) : `, ${supportedProperty(p2)}`
   if (!prefixedValue) return p1 || p2
diff --git a/src/supported-value.test.js b/src/supported-value.test.js
index a047a5b..c6046aa 100644
--- a/src/supported-value.test.js
+++ b/src/supported-value.test.js
@@ -57,6 +57,14 @@ describe('css-vendor', () => {
       expect(supportedValue('transition', 'var(--something)')).to.eql('var(--something)')
     })
 
+    it('should return custom CSS variable with fallback CSS variable for transition property as it is', () => {
+      expect(supportedValue('transition', 'var(--something, var(--another-thing))')).to.eql('var(--something, var(--another-thing))')
+    })
+
+    it('should return custom CSS variable with fallback CSS variable having another CSS variable as fallback for transition property as it is', () => {
+      expect(supportedValue('transition', 'var(--something, var(--another-thing, var(--another-another-thing)))')).to.eql('var(--something, var(--another-thing, var(--another-another-thing)))')
+    })
+
     it('should return custom CSS variables for transition property as they are', () => {
       expect(supportedValue('transition', 'width var(--width), height var(--height)')).to.eql(
         'width var(--width), height var(--height)'