Twelve bighorn ewes (Ovis canadensis), killed by vehicular traffic in southern British Columbia, were examined for pregnancy; 11 were pregnant, 4 of them were carrying twins. The absence of twins among bighorn sheep frequently has been noted by biologists recording their field observations. A recent author (Woodgerd, W. 1964. Population dynamics of bighorn sheep on Wildhorse Island. J. Wildl. Mgmt. 28(2):381391) summarized his own observations of a bighorn sheep population on Wildhorse Island (Montana) plus a literature review of six authors and could find only one reference to an authentic twin birth among bighorn sheep. The following observations suggest that twins may occur more frequently than published data indicate. An opportunity to examine reproductive tracts from bighorn sheep arose during the winter of 1963-64. Heavy snows forced wintering ewes and lambs down along Highway 97 in the vicinity of Vaseux Lake (Okanagan Valley) in southern British Columbia. During a 4-month period from Table 1. Age and frequency of single and twin pregnancies in female sheep killed by traffic in the vicinity of Vaseux Lake, British Columbia. AGE NUMBER NOT PREGNANT (YEARS)* EXAMINED PREGNANT Single Twins Single Twins 3 4 1 2 1 4 5 2 3 5 1 1I 6 2 2 * Age determined by growth rings on horns (Taber, R. D. 1963. Criteria of sex and age. Pages 184-186. In Henry S. Mosby (Editor), Wildlife investigational techniques. Printed for The Wildlife Society by Edwards Brothers, Inc., Ann Arbor, Michigan. xxiv -+419 pp.) late November, 1963, until late March, 1964, 13 ewes were killed by highway traffic. During the winter of 1964-65 two more ewes were killed in the area. Table 1 summarizes information about age and rate of pregnancy of 12 sheep collected and examined by members of British Columbia's Fish and Game Branch in the south Okanagan. Twelve ewes were examined for pregnancy and in four cases twins were found. The most advanced twin pregnancy was observed February 15, approximately 2 months before lambing, which begins during mid-April. All twin fetuses appeared healthy. One 6-year-old ewe, killed February 6, 1964, had an extra-uterine male fetus attached to the right body wall within the abdominal cavity. I was unable to examine his specimen, but it was reported that the fetus appeared normal in its development but was tightly enclosed within the fetal membranes. Observations of the Vaseux herd are limited but an occurrence of live twins has never definitely been established. On June 18, 1964, a coyote was observed harrying a group of ewes and lambs. One ewe and two lambs consistently remained together and in one instance left the main group of sheep and moved out onto a small ledge which provided b tter protection from the coyote. These lambs may have been twins. Received for publication July 6, 1965.