Is it legal to purchase real estate "subject too" the existing mortgage. The short answer is yes, it is legal. But, it is a lot more complicated than that, there are significant risks and the lender does have rights. I recommend that before you spend a lot of money on this purchase you schedule a free case assessment with one of our real estate attorneys to discuss your options, things to be concerned about, risks, remedies, and how to mitigate as much risk as possible. As well as the costs involved in protecting your investment and the contract.