Members voted 24-14 against the proposal to form an independent working party which would have been charged with coming back to the States with a recommendation for how to introduce new legislation.
The second day and third days of debate were largely dominated by speakers against assisted dying.
Deputies have approved a proposition to further investigation developments in end of life care, with some States members commenting afterwards that it 'leaves the door ajar' to an assisted dying debate returning to the States in the future.
Deputy Gavin St Pier, who led the requete that brought the subject to the Assembly, said afterwards: 'Naturally we are disappointed with this result, although it was not entirely unexpected.'
'We believe that a majority of the population do support a change in the law. However, we live in a representative democracy and our parliamentary assembly, the States of Deliberation, has by majority, made a democratic decision which settles the matter in Guernsey.'