The group therapy is based on some techniques found in Buddhism
Group-taught meditation is as effective as staying on drug treatments for stopping people slipping back into depression, say UK scientists.
Compared to one-to-one sessions, or medication, "mindfulness-based cognitive therapy" (MBCT) is cheaper for the NHS, they say.
The trial of 123 people found similar relapse rates in those having group therapy and those taking drugs.
The study was published in the Journal of Consulting and Clinical Psychology.
Recent years have seen much more evidence that so-called "talking therapies" can be as effective as drugs in alleviating mild to moderate depression, and health secretary Alan Johnson recently announced millions in new funding for the treatments.
However, this is the first time, according to its authors, that a group therapy has been shown as an alternative to a prescription.
The study, funded by the Medical Research Council, found MBCT, developed in 2002 by a team of psychologists from Canada, Oxford, and Cambridge, was actually more effective than medication in improving patients' quality of life.
The sessions involve the teaching of meditation techniques based on some found in Buddhism.
The aim is to teach skills which help patients recognise and cope with their tendency towards depression.
Di Cowan, from East Devon, had suffered from depression since his late teens.
The 53-year-old said: "It's helped me immensely - it's given me the ability to come up against something that would have previously thrown me, think it through, come up with a solution and then move on.
"My view of the world has changed and I look at life in a new light."
One of those championing the technique is Professor Willem Kuyken, of the Mood Disorders Centre at the University of Exeter.
He said: "Our results suggest MBCT may be a viable alternative for some of the 3.5 million people in the UK known to be suffering from this debilitating condition.
"I think we have the basis for offering patients and GPs an alternative to long-term antidepressant medication."
Marjorie Wallace, the chief executive of mental health charity SANE, said the charity would be helping to fund future research into how "ancient meditative techniques" could work together with modern psychotherapy in people with long-term depression.
She said: "We are delighted that this study shows the potential of Mindfulness-Based Cognitive Therapy as an alternative for the treatment of severe and recurring depression.
"Just one in five depressed callers to our helpline report that they are receiving any kind of talking therapy, which is recommended as a first line of treatment."