It will receive evidence from experts and the public before publishing a report in December 2011.
Earlier this year the Crown Prosecution Service issues new guidelines.
The clarification of the law, issued in February came after right-to-die campaigner Debbie Purdy, who has multiple sclerosis, took her case to the House of Lords after the High Court and Court of Appeal held it was for Parliament, not the courts, to change the law.
Ms Purdy, from Bradford, West Yorkshire, wanted to know if her Cuban husband, Omar Puente, would be prosecuted if he helped her travel to Switzerland to end her life.
‘Report of quality’
Lord Falconer, a former justice secretary, said the commission would consider what changes should be made to the law.
But he said: “We approach the task, each one of us, determined to come up with a report of quality which will be respected as an objective, dispassionate and authoritative analysis of the issues and as providing a reliable way forward.
The commission includes former Metropolitan Police commissioner Lord Blair of Boughton, the Reverend Canon Dr James Woodward, Anglican priest and Canon of St George’s Chapel, Windsor and Dr Stephen Duckworth, founder and chief executive of Disability Matters Ltd.
Richard Hawkes, chief executive of the disability charity Scope, said: “Assisted suicide is a highly-charged and emotional issue, and there is a desperate need for a real and open debate.
“However, we are deeply concerned that this pseudo ‘commission’ will not reflect the concerns and fears of many disabled people. When it is funded by supporters of legalising assisted suicide and without a formal remit from government, we would question how independent this commission really can be.”
The commission has not been set up by the government and a Ministry of Justice spokesman said: “The government believes that any change to the law in this emotive and contentious area is an issue of individual conscience and a matter for Parliament to decide rather than government policy.
“Parliament has decided on a number of occasions that the law on assisted suicide should not be changed. In a free vote on the issue on 7 July 2009, during their consideration of the then Coroners and Justice Bill, the House of Lords rejected an attempt to decriminalise assisted suicide in circumstances where terminally ill people are helped to travel to countries where assisting dying is lawful,” he added.