Over 100 guests were welcomed to No 10, including long-serving volunteers, trustees, patrons and a number of children, young people and families cared for at the Sutton Scotney hospice.
Speaking after the event, Steve Brine said: "This was so kind of Samantha Cameron and a superb pre-cursor to Hospice Week for Naomi House. We all know what a special place we have in Naomi House and I was so very proud to have them here in No.10 Downing Street along with many supporters, families and team members. We now look forward to the Royal Visit by the Duchess of Cambridge on Monday."
Chris Robinson, chief executive at Naomi House, said: "We were delighted to be able to thank our supporters from across the region at this special event in London's most well-known address. We are extremely grateful to Mrs Cameron for inviting us into her home.
"It was a wonderful opportunity to express our gratitude to just a few of the thousands of kind, generous and selfless individuals who have made such a difference to the lives of life-limited children and young people throughout Naomi House's existence."
The reception followed a meeting in Parliament recently, where David Cameron pledged his support for Naomi House to chairman Khalid Aziz, and local MPs Steve Brine and John Glen (Salisbury).