Police were called to an address in High Holme Road shortly before 8.30pm on Monday evening after being informed by the ambulance service.
Officers tragically discovered a woman and a child at the property who had died.
Lincolnshire Police are appealing for anyone who has seen Daniel Boulton or has any information to get in touch immediately.
The public are being warned not to approach him and instead call 999.
A force spokesman said: "We are urgently appealing for information or sightings of Daniel Boulton following the death of a woman and child in Louth.
"Officers were called to an address on the town’s High Holme Road at 8.29pm, last night (31st May), after being informed by our colleagues in the ambulance service.
"Sadly, a woman and a child were found dead at the property.
"An investigation has been launched and we are appealing for any sightings or information that could help us to find Daniel Boulton, who is aged 29.
"You should not approach him but instead call 999 quoting Incident 445 of 31st May."