Researchers found that women who took part in group singing sessions with their babies experienced a much faster improvement in their symptoms than those who did not.
The study, published in the British Journal of Psychiatry, looked at 134 mothers with post-natal depression.
Early recovery is seen to be crucial to limit effects on mother and baby.
Post-natal depression is estimated to affect one in eight new mothers.
Previous studies have indicated singing can help improve the mental health of older people and those with dementia, but this is the first controlled study of its effect on post-natal depression.
The women were placed into three groups:
one took part in group singing
another took part in in creative play sessions
a third group received their usual care, which could include family support, antidepressants or mindfulness
Mother and baby music groupImage copyrightGETTY IMAGES
The singing workshops saw the mothers learning lullabies and songs from around the world with their babies and creating new songs together about motherhood.
And those with moderate to severe symptoms of post-natal depression reported a much faster improvement than mothers in the usual care and play groups.
All the groups improved over the 10 weeks, but in the first six weeks the singing group had already reported an average 35% decrease in depressive symptoms.
Principal investigator Dr Rosie Perkins said the study, although small, was significant because it was important to tackle the symptoms as quickly as possible.
"Post-natal depression is debilitating for mothers and their families, yet our research indicates that for some women something as accessible as singing with their baby could help to speed up recovery at one of the most vulnerable times of their lives," she said.
Lead author Dr Daisy Fancourt, from University College London, said singing was another useful therapy to offer women.
"Many mothers have concerns about taking depression medication whilst breast-feeding and uptake of psychological therapies with new mothers is relatively low," she said.
"So these results are really exciting as they suggest that something as simple as referring mothers to community activities could support their recovery."