In an open letter to The Times newspaper, Rt Revd James Newcome said changing the law would put "many thousands of vulnerable people at risk".
The Bishop of Carlisle also said terminally ill people should not have to choose between dying early and feeling like they're being a burden to loved ones.
Rt Revd Newcome also cited statistics from the American state of Washington, which say 60 percent of people were concerned that terminally loved ones would feel under pressure to end their lives early, since the Death with Dignity Act was passed in the city of Oregon in 2013.
He was responding to comments made by the former Director of Public Prosecutions and Labour MP Keir Starmer, who called for the law to be changed so people who help terminally-ill loved ones to die can't be prosecuted.
Keir Starmer also said people should not have to "traipse off to Switzerland" if they wanted to end their life.
Mr Newcome said: "His [Keir Starmer's] support for the Assisted Dying Bill... [has] no achievable outcome other than facilitating some individuals at the cost of placing many thousands of vulnerable people at risk.
"Terminally ill people deserve to be surrounded with love, compassion, and care - not called to make a choice between dying prematurely and being a burden.
"The only effective safeguard against this pressure is to keep the law as it is."
It's less than two weeks until politicians debate Labour MP Rob Marris' Assisted Dying Bill.
If it passed as it currently stands, it would allow a terminally-ill person with less than six months to live to be prescribed lethal drugs if two separate doctors agreed that the person had demonstrated a "clear and settled intention" to die.
A High Court judge could intervene if necessary.