In season four , Elena is faced with the tough decision of whether to die or to feed on human blood so she can fully transition into a vampire . Elena , after realizing Stefan 's desperation to keep her alive , decides to complete her transition . Her relationship with Stefan ends , allowing her to begin a proper romance with Damon . Although , it is later revealed there is a sire bond between them . Sometime later whilst searching for the cure for vampirism , Jeremy is fed to the immortal Silas by Katherine . As a result , Damon used the sire bond to convince her to turn off her humanity , due to her incredible grief over losing her brother and the last remaining member of her family . Elena became ruthless without her emotions , going on killing sprees and being very hateful towards her friends . Towards the end of season four , Damon kills Matt in front of Elena to trigger her grief . After revealing that Matt had the Gilbert Ring on , Elena 's humanity was switched on and her emotions were focused on hate towards Katherine for killing Jeremy . Season four ended with Bonnie as a ghost after bringing Jeremy back to life and Elena fed Katherine the cure for vampirism in a moment of desperation as she was about to be killed . Elena had chosen Damon as the Salvatore that she loved .

Question: when does elena turn into a vampire in the tv series
Answer: season four