The six-month Lone Parent Support trial, run in conjunction with charity One Parent Families, began in March at an Asda store in Clapham, south London.
The retailer found that staff turnover at the store was reduced by 5% after the introduction of a telephone helpline, website and e-mail service to provide extra support to lone parent workers.
Meanwhile, Asda said it would no longer ask people applying for a job at its UK stores to give their date of birth. The move goes beyond new age discrimination legislation that is due to come into force on 1 October.
David Smith, people director at Asda, said: "We have thousands of colleagues working with us who are past the age of 65."