I'm not sure exactly how it works, but to be a part owner of the house, she would have to provide that part of the purchase cost. Otherwise you're "gifting" your daughter one-third of the purchase price and that figures into gift tax (and ultimately inheritance tax) calculations later on. This stuff gets complicated remarkably quickly - and more so if either of you has any other heirs (other children or surviving parents on either side). Just remember, too, that on the death of one of you, your daughter would get her share of the decedent's share of the house - so her part of the decedent's one-half of the house unless you set it up in some other way. So at that point, the surviving parent would have shared ownership of the house with the daughter. There are also considerations of usufruit that can be used to make things a bit smoother in some cases.