One hundred four neonatal (fawns) and 40 adult female (does) pronghorn antelope (pronghorns) (Antilocapra americana) were captured on the Hart Mountain National Antelope Refuge (HMNAR) in Lake County, southeastern Oregon, between 13 May 1996 and 26 May 1997. Blood and fecal samples were taken for an investigation of low fawn survival that may be due to disease and/or poor nutrition. No abnormalities were found in hematological parameters of adult does (n = 40) or fawns (n = 44 to 67). In general, there were lower serum total proteins (TP) and Blood Urea Nitrogen (BUN) concentrations in this population than in other populations from Alberta, Canada; Idaho; and Baker City, Oregon. Mean BUN values in does were significantly lower (p < 0.001) in December than March. The duration of this apparently low protein content of the December diet may affect the weight of the newborn and consequent survivability if it should continue into late gestation (March-May). Serum copper (Cu) levels in does (range 0.39 to 0.74 ppm) were considered marginal when compared to domestic animals and some wild ungulates. Fawns had low but apparently normal Cu levels at birth and reached the does' marginal values in about three days. Whole blood and serum Selenium (Se) levels (<100 ng/ml) were considered to be marginal to low in most segments of the pronghorn population in this study. However, serum levels of vitamin E (range 1.98 - 3.27 pg/ml), as determined from the does captured in March, are apparently sufficient to offset any signs of deficiency due to low Se levels. No clinical signs of Cu or Se deficiency were observed. Does captured in December 1996 were tested for neutralizing antibodies to Brucella spp. (n = 20, neg.), Leptospira spp. (n = 20, neg.), bluetongue virus (n = 20, 35% pos.), epizootic hemorrhagic disease virus (n = 20, 30% pos.), respiratory syncytial virus (n = 18, neg.), parainfluenza virus type 3 (n = 18, 67% pos.), infectious bovine rhinotracheitis (n = 18, neg.), and bovine viral diarrhea (n = 18, neg.). Seventeen fawns (9F,8M), nine in 1996 and eight in 1997, survived until at least mid-July each year. Fifty-five of 87 dead fawns were necropsied. Predation by coyotes (Canis latrans) accounted for the majority of fawn mortality (62%), as determined by necropsy, during the two combined summer periods. Other causes of mortality for the combined years included predation by eagle (4%), dystocia (2%), septicemic pasteurellosis (5%), starvation/weak fawn syndrome