Head and body length is about 35-110 mm, tail length is 15-56 mm, and weights range from 16.5 to 28 grams. Color varies widely from reddish brown to deep black above and paler below. Horseshoe bats get their name from the leaflike structure of skin around the nose which forms a horseshoe around the mouth. When flying, they keep their mouths closed while emitting ultrasonic sound through the nostrils.

Rhinolophus ferrumequinum hibernates during which body temperatures have been recorded at 8°C, in contrast to 40°C during normal activity. Mating occurs during the fall, but ovulation and fertilization are delayed until spring. Gestation takes about 7 weeks and a single young is produced in late spring. Females have two functioning mammae and two "dummy teats" which the infant may clasp while being transported by its mother. Sexual maturity occurs by 2 years of age. When roosting, this species wraps itself with its wings. The broad wings have rounded ends and the flight pattern resembling that of a butterfly.

Insects and spiders are the main food source. A large insect may be tucked into the wing membrane under the arm while the bat manipulates it with its mouth.

Rhinolophus ferrumequinum is declining rapidly due to habitat pressures including disturbance, vandalism and practices resulting in a loss of large prey insects. The distribution of R. ferrumequinum is Algeria, Morocco, and Tunisia; S Europe from Portugal to Greece and north to S England, the Netherlands, S Germany, Austria, Czech Republic, Slovakia, and Bulgaria; Turkey, Cyprus, Georgia, and Azerbaijan; Urkrain, Crimea, and Caucacus regions; the Mediterranean coast from Turkey to Israel and Jordan; NE Iraq, Iran, Turkmenistan, Uzbekistan, S Kazakhstan, Afganistan, Pakistan, N India, Nepal, Sikkim, China, Korea, and Japan; adjacent small islands. Records at some localities in northern Europe (e.g. the Netherlands) apparently reflect temporary northern range extensions.