Sussex Police are asking - have you seen Christopher Poulter?
The 27-year-old left his home in Cowfold on February 14 and said he was going camping but has not been seen since.
Christopher took a sleeping bag but has not been in contact with his family.
Sergeant Colin Garman said: “We’re becoming increasingly concerned for Christopher as the days go by.
“There is nothing to suggest that he is not safe and well but it has now been four days since he last spoke to his family and we need to get in touch with him.
“If you know where he is or have seen him please contact us so we can check he is ok.”
Anyone with information should call 101 quoting serial 427 of 14/2, email email@example.com or call the independent charity Crimestoppers anonymously on 0800 555111.