We live in Massachusetts & gave a deposit on an apartment when submitting a tenant application. We ended up being apporved butmchanged our mind about renting that apartment and called the apartment owner. He had cashed the check and now says he doesn't need to return the money. Is this legal?

Did you actually sign a rental agreement? If so yes, if not, no not legal.

Did you actually sign a rental agreement? If so yes, if not, no not legal.. No rental agreement was signed. This was a deposit while he was checking credit and "approving" us

Read the paper work, normally you give a deposit to hold the apartment. and if you don't take it, since they saved it for you. They keep the money, that is how all of my agreements were, Read the application, you would have signed a application for the apartment.

If you signed application, read it. I am a landlord and my application does not state that, but if tenant is interested I have them sign a hold lease premises contract with deposit. That states that deposit is only refunded if I do not approve them for the apartment. If they decided they do not want apartment the deposit is forfeited. Check the application for any mention of this. Otherwise if it is not stated on the application then the landlord would have to refund you the money. You would have to take the landlord to court to do that if he does not refund.