The doctor, a consultant anaesthesiologist, died in the morning, they added.
LNJP Hospital is a dedicated COVID-19 facility under the Delhi government.
"He lost the battle today after a valiant fight," a hospital source said.
Sources said the doctor died in the ICU of Max Smart, a dedicated COVID-19 facility in Saket.
Several hundreds of healthcare workers have been infected with COVID-19 till date in Delhi.
A doctor from Fortis Escorts Heart Institute in Okhla in south Delhi recently died of the novel coronavirus infection.
A 39-year-old doctor from Odisha had died of COVID-19 in the ICU of the Delhi government-run Rajiv Gandhi Super Speciality Hospital on June 20. KND IJT