Calving and calf production were studied in an experimental reindeer (Rangifer tarandus L) herd in Inari, Kaamanen (69°10'N) in northern Finland. Most of the calving took place between May 10 and 29; 50% of the calves were born up to 22.5. and 90% up to 29.5. The percentage of calves (calves/hinds proceeding year) was on average 79.2%. The newborn sex ratio was 1:1. There was a large range (1.8 to 8.5 kg) in the birth-weight of newborn calves; male calves weighed about 0.3 kg more than female. The total loss of calves during summer and autumn was about 34.5% (range 6.3 to 100.0%). During the calving period 111 calves (12.2%) died. They were usually younger than one day, and on average weighed 1.3 kg less at birth than calves who lived until autumn. The hinds of calves dying very early were usually young and calving for the first time. The autumn-weight of hinds correlated significantly (r = 0.49) with the birth-weight of their calves. Over-5-year-old and over 80 kg hinds bore the heaviest calves (mean weight 6.3 kg) and the survival of these calves was very good. The first hinds to calve in the spring (calving up to 22.5.) are 5-year-old and older, which arc also the heaviest and produce the most vital calves.