The 58-year-old is paralysed from the neck down and can only communicate through blinking.
He has described his life as a "living nightmare" since suffering a stroke in 2005, leaving him with locked-in syndrome.
His High Court case is higher than any previous challenges in England and Wales to the law surrounding assisted suicide.
Mr Nicklinsons case differs from some in the past such as Diane Pretty's in 2001, because he would be unable to take lethal drugs even if the courts deemed it acceptable.
Instead, because he is paralysed, someone else must kill him, technically deeming the act murderous.
Mr Nicklinson's legal team will quote Article 8 of the Human Rights Act - the right to repsect for private and family life.
They will also argue that the only way to end Mr Nicklinson's suffering is to let him be killed, rather than leaving him to what he describes as " a 'life' of increasing misery."
It is understood that, if necessary, the verdict is subject to an appeal.