Sitting in a small room with her family members, 92-year-old Hiraben watched live coverage of the gala event.
She seemed unperturbed by scores of cameramen and reporters who had crowded the room to seek her reaction.
Modi was blessed by his mother at her home in Gandhinagar after BJP won the electoral mandate to form the next government at the Centre.
"He has my blessings and he will lead the country towards development," she had said after blessing her son.
She stays with her other son Pankaj Modi in Gandhinagar.