Six of the deaths were reported in the western state of Maharashtra, while Rajasthan, Andhra Pradesh and Karnataka have also reported deaths due to swine flu, the BBC reported Friday.
Nearly 130 others have been infected with the virus.
India's Health Ministry said it is not sure what caused the sudden outbreak.
"The Health Ministry is monitoring the situation and there is no cause for worry. The states where cases had been reported have been advised to step up surveillance to control the further spread of the virus," said Health Secretary P.K. Pradhan.
One case of swine flu has popped up in Mumbai, the Times of India reported.
A 6-year-old boy tested positive for the H1N1 virus Wednesday, executive health officer Dr. Anil Bandivadekar said.
"The patient has already been started on Tamiflu and doctors have told us that he is stable. We will be monitoring his condition," he said.
An estimated 450 died when the virus first arrived in India in 2009.
Dr. Abhay Chaudhary, director of the Haffkine Institute, said: "Influenza or influenza-like illness is common in this season and the extended winter only made it worse. But H1N1 is more or less like other forms of seasonal virus circulating in the air now.
"We have to remain alert. We have to keep in mind that influenza is complicated and can kill, so precautions must be taken," he said.