Golden takin (Budorcas taxicolor bedfordi; Bovidae), is found only in the Qinling Mountains of western China. Radio-tracking and direct observations were carried out at Foping Nature Reserve in Shaanxi Province to study social behavior of the takin, including group sizes, group composition and group stability. Golden takins are gregarious. Mean group size among 1,039 takins sighted in groups was 10.82 ± 0.96 (n = 96) individuals excluding solitary individuals. The largest group had 59 animals and 50% of the animals were seen in groups larger than 15 individuals during the study period. The results from this study indicate that the core social unit of golden takin is adult females accompanied by their offspring of more than one generation. 53.1% of all groups included more than one adult female, and 63.3% of all groups had more than one subadult or calf. The mean size of groups formed by adults with subadults or calves was 14.83 ± 2.34 (n = 29) individuals. The ratio of adult females to adult males was 1.0 : 0.49, skewed in favor of females. The results also show that takin groups are unstable and group composition can vary over time. Reproductive activity of adult males, subadult leavings from their mother’s group and human disturbance are suggested to be factors responsible for group size variation.