In neonate and juvenile male alpacas the prepuce adheres to the glans penis, making extrusion of the penis impossible. The aim of the present research was to determine the relationship between age of prepuce separation and circulating levels of total testosterone. A total of 98 one and two year old male alpacas from Corpacancha (Junfn, Perú) were studied. Serum progesterone levels were determined by radioinmunoassay from blood samples and prepuce separation was determined by manual retraction. Data on live weight, testicular size and age were also recorded. Only 4% of the one year olds (n= 1122) and 49% of the two year olds (n= 37176) were free of adhesions and these animals exhibited higher levels of serum testosterone relative to the animals without prepuce separation.