Yponomeuta cagnagella, the spindle ermine, is a moth from the family Yponomeutidae, the ermine moths.

The wingspan of the moth ranges from 19 to 26 millimetres.

Forewings are white; four longitudinal series of few black dots, first not reaching middle, second beginning near before middle, lowest including 4-7 dots; some additional black dots before termen; cilia white.

[2] Flight time ranges from the end of June to October.

The host plant of this moth is European spindle.