Police said the boy was found by staff at the Bell Waste Control site on Winterton Road, Scunthorpe, at about 09:30 BST.
His body was found among items being sorted for recycling. The scene has been cordoned off.
Humberside Police said they were concerned for the baby's mother and urged her or anybody who knows her to come forward.
A force spokesman said: "At this time, very little is known in terms of the circumstances which led to the baby seemingly being discarded.
"We are concerned that the baby's parents, in particular his mother, may need help and support following the loss of her child and as such she may be very vulnerable at this time
http://www.bbc.co.uk/news/uk-england-humber-17926883