The separation of young dogs from their mother at the age of 6 weeks had a negative effect on the physical condition and weight gain of separated pups compared to that of pups with maternal contact till 12 weeks. Disease susceptibility and mortality was higher in pups with a shorter maternal contact period. These factors were related to behavioural measurements of separation stress. However, early separation had no significant advantage to socialisation with humans, provided that separated and nonseparated pups had daily human contact. Early separation therefore did not improve dog/human bonding processes but lowered condition and increased mortality in separated pups.