At least 150 venomous snakes were seized from a man in Badin, but most of them died as the reptiles could not be shifted to a safe place, SAMAA TV reported Thursday.
The CIA police searched a suspicious car when they found the snakes in cloth bags Wednesday night.
Three cobras, 30 krait (locally called Piyan bala), 10 double-headed snakes, 15 Korar snakes and 92 Lundi snakes were seized from the man.
The CIA police later handed over the snakes to Sindh wildlife officials.
However, most of the snakes died of suffocation as the wildlife staff did not take them out of the bags even after 24 hours, according to our correspondent.
They were waiting for senior officers to come.
The man, identified as Allah Dino Jogi, was travelling from Tharparkar to Karachi.
He was heading to Karachi to look for customers who purchase rare snakes worth millions of rupees. The venom of the rare snakes is smuggled abroad, officials said.
A case has been registered against the accused but he has yet to be produced in court.