André Zoller, 64, from Consdorf, left his home late on Sunday morning and has been missing ever since.
He is known to enjoy travelling by bus or train without any particular destination in mind.
The missing man is wearing a grey striped jumper, dark grey trousers and dark shoes. He is not wearing a jacket.
Anyone with information about his whereabouts is asked to contact Echternach police by telephone on (+352) 24472-1000 or by email at police.echternach@police.etat.lu.
