The legislator and others took the pledge at a function in his Bicholim constituency yesterday.
"IMA's Goa branch has started a drive for creating awareness about organ donation. An online initiative has also been launched on our website," IMA's senior member Shekhar Salkar told PTI.
He said Patnekar was "impressed with the initiative and willingly agreed to register as a donor."
"That was a great surprise for us. When the MLA came forward, people too followed him," Salkar said.