On January 24, 1966, Indira Gandhi made history by being sworn in as India's first woman Prime Minister. Her ascension to the nation's highest political office followed a period of political uncertainty triggered by the sudden demise of Prime Minister Lal Bahadur Shastri earlier that month. This landmark event positioned India as one of the earliest sovereign nations to be led by a woman.

The vacancy in the Prime Minister's office arose unexpectedly when Prime Minister Lal Bahadur Shastri passed away in Tashkent, Uzbekistan (then part of the Soviet Union), on January 11, 1966, hours after signing the Tashkent Declaration, a peace treaty with Pakistan. His death created a leadership vacuum within the ruling Indian National Congress party, prompting an internal contest for the Prime Ministership.

Two prominent figures emerged as contenders for the leadership role: Indira Gandhi and veteran Congress leader Morarji Desai. Desai, known for his administrative experience and conservative stance, put forward his candidature. Indira Gandhi, daughter of India's first Prime Minister Jawaharlal Nehru, had served as President of the Indian National Congress from 1959 to 1960 and later as Minister of Information and Broadcasting in Shastri's cabinet. Her political lineage and recent ministerial experience positioned her as a strong candidate.

The selection process took place through an internal election within the Congress Parliamentary Party. On January 19, 1966, the party members cast their votes to elect their new leader. Indira Gandhi secured a decisive victory, garnering 355 votes against Morarji Desai's 169 votes. This clear mandate from the party paved the way for her to assume the Prime Ministership.

Following her election as the leader of the Congress Parliamentary Party, Indira Gandhi officially took the oath of office on January 24, 1966, at the age of 48. Her swearing-in ceremony marked the formal beginning of her first tenure as Prime Minister, a period that would profoundly shape India's domestic and foreign policies for nearly two decades. Her appointment was widely noted internationally, highlighting the progressive potential of India's democratic framework in elevating a woman to such a powerful position at a time when female heads of government were a rarity globally.

Her initial period in office was met with various challenges, including food shortages, economic difficulties, and ongoing geopolitical pressures. Despite the initial skepticism from some quarters regarding her experience, Gandhi quickly began to consolidate her authority, embarking on a path that would see her become one of India's most influential and enduring political figures.