The boat's captain told the coastguard at 02:00 am local time (2300 GMT): "We are sinking. There are 30 people in the boat," before contact was cut off, according to the private Dogan news agency.
Turkish coastguard recovered 24 dead bodies and rescued 12 immigrants whose nationalities were not immediately available. The search and rescue operation was still continuing.
The boat that sank off Turkey's Aegean coast was supposed to take the illegal immigrants to the Greek island of Lesbos, Dogan reported.