The appointment came following a major cabinet reshuffle by King Salman, who with the selection has put in place a new generation to succeed him.
55-year old Prince Mohammed bin Nayef, the current Saudi Arabia Interior Minister and nephew to the new Saudi King, King Salman, has been appointed the new crown prince of the oil-rich country.
Also appointed is the king's son, Prince Mohammed bin Salman, who has been made deputy crown prince and the foreign minister, Prince Saud al-Faisal, has been replaced.
According to BBC analyst, Kim Ghattas the latest reshuffle shows King Salman is firmly turning the page on the era of his predecessor and pushed aside allies of the late monarch such as his half-brother Muqrin bin Abdul Aziz, who until today (Wednesday) was crown prince.
The rise of Prince Mohammed bin Nayef and Prince Mohammed bin Salman, who is believed to be in his early 30s, means that for the first time a grandson of the kingdom's founder, King Abdul Aziz, is in line to rule.
News watchers believe the appointment of Prince Mohammed bin Nayef as crown prince and deputy premier is likely to be welcomed by the United States, with whom he has a close relationship. Also he is known for his strong stance against jihadist militants and narrowly survived an assassination attempt by al-Qaeda in the Arabian Peninsula suicide bomber in 2009.
First appointed defence minister in January, before overseeing a military operation by a Saudi-led coalition against Houthi rebels in Yemen in the last month, the new Deputy Crown Prince and Second Deputy Premier has enjoyed a meteoric rise within the Saudi leadership.
Meanwhile, the most senior woman in the Saudi government, Nora al-Fayez, has been removed as deputy education minister for girls, a post she had held since 2009.
al-Fayez had sought to introduce sports programmes for girls in state-run schools but was opposed by religious conservatives.