1. Sixty-four Dorset Horn ewes and sixty Half- Bred ewes were X-rayed in the pelvic region at stages of pregnancy between 51 and 110 days.
2. Diagnosis of pregnancy and estimates of the number of foetuses carried were made from the X-ray film.
3. Over the range of gestation stages examined, interpretation of the number of foetuses present was found to be most accurate at stages between 91 and 110 days.
4. An accurate estimation of whether the ewe is pregnant or barren can be made from 50 days onwards.