This includes the United Kingdom, Iran, Russia, Kazakhstan, Turkey, Algeria, India, Pakistan, Germany, Italy, France, Spain, Portugal and many other countries.

The flowers are white, about 1 cm (0.4 in) long, with a yellow-edged labellum and they usually open only during the warmest and brightest hours of the day.

[7] Another investigation indicated 9 mycorrhizal partners (still fewer than those recorded for Cephalanthera damasonium): Bjerkandera adusta, Phlebia acerina, Sebacinaceae, Tetracladium sp., and Tomentella sp.

[9][6] Cephalanthera longifolia is common in some parts of its European range, such as southern France and Spain, but endangered particularly in northern areas such as Belgium.

In Britain and Ireland it is a quite uncommon and declining species, and conservation work is being carried out at a number of sites to safeguard it (see also Galley Down Wood).

Sword-leaved helleborine usually grows in damp woodland places (mainly oak and beech), forest edges and rocky slopes.