This is the president's second lowest score since he was sworn-in over two years ago.
Since he was inaugurated as president, this is Buhari's second lowest score after he earned a 37% approval rating in August 2016.
February's abysmal 38% score represents a 2-point decline from his 40% approval rating in January 2018.
The president's disapproval rating stands at 44%, a 1-point increase from January, while 18% of survey participants were undecided.
Details of the poll, based on geo-political zones, showed that the president is most popular in the northeast zone with a 62% approval rating, a 4% drop from January, and least popular in the southeast zone with only 8% approval rating, worse than 12% from January.
In the other zones, he has a 61% approval rating in the northwest, 37% in north central, 29% in the southwest, and 14% in the south south.
The president's performance in agriculture and food security got a 37% 'excellent+good' approval rating (the highest) while he was rated 10% for his performance on poverty alleviation.
The president got his most favourable rating from respondents within the ages of 18-35 (40%), and his least favourable from people older than 60 (29%), while 37% of Nigerians between the ages of 36-60 approved of his performance.
Nigerians that were interviewed for the survey include civil servants, traders, businessmen/women, farmers, artisans, religious leaders, students, youth corps members and the unemployed.
NOI Polls periodically assesses the opinion of Nigerians on socio-economic and governance issues with its Opinion Polling Centre (NOPC) dedicated to capturing the opinions of Nigerians daily.
Interviews are randomly conducted nationwide as Nigerian phone owners aged 18 years and above are selected across the six geopolitical zones in the country.
The president's approval rating in February could not have been helped by reports from international agencies that revealed his administration is struggling with the economy and against anti-corruption.
In a report by Transparency International (TI) released on February 21, Nigeria still ranks as one of the most corrupt countries in the world.
While the country is jointly ranked 148/180 alongside Guinea and Comoros, African countries ranked higher than Nigeria include: Botswana (34th), Rwanda (48th), Namibia (53rd), and Kenya (143rd).
According to the Civil Society Legislative Advocacy Centre (CISLAC), which is Transparency International's national contact, the new index is worrying as it reflects the inability of President Buhari's administration to combat corruption like he promised.
Its assessment read, "This fresh setback in the fight against corruption confirms that grand corruption, political corruption, nepotism, favoritism and bribery persist in Nigeria at all levels.
"It is CISLAC's view that the negative perception is mainly a consequence of the inability to combat grand corruption and astronomical plundering of public coffers costing the Nigerian taxpayers around 25% of annual GDP.
"Since the current administration has come to power on the anti-corruption ticket, no significant politically exposed person has been duly sentenced on anti-corruption charges."
According to another report released by the International Monetary Fund (IMF) on February 28, Nigerians are getting poorer despite the country's slow recovery from a devastating recession.
While the report expressed the need for urgent economic reforms expected to help the government "muddle through" in the medium term, the IMF was also wary of the fact that next year's election could consume the gains.
The report read, "Comprehensive and coherent economic policies remain urgent and must not be delayed by approaching elections and recovering oil prices.
"Higher oil prices would support a recovery in 2018 but a 'muddle-through' outlook is projected for the medium term under current policies, with fiscal dominance and structural constraints leading to continuing falls in real GDP per capita."