Nawab Ali Mohammad Ali (45) was arrested in 1999 along with six other Pakistanis who had sneaked into India with a huge stock of arms and ammunition, police said.
All the seven were produced before a local court in Kutch, which awarded death penalty to Ali.
He had sought mercy from the then President Pratibha Patil, who commuted his death penalty to life imprisonment, police said.
"He had been kept in Ahmedabad jail and was transferred here some five months back," Rajkot district jail superintendent A K Vyas said.
"Nawab Ali was suffering from kidney disease and was first admitted to civil hospital here from where he was referred to Ahmedabad for further medical treatment where he died last night," Vyas said.
He said procedure was on to send the body to Pakistan.
