The amount showed the ex-military ruler and minister of petroleum had been living a “Spartan lifestyle”, his spokesman Garba Shehu said.
The BBC’s Will Ross says the assets are loose change for Nigerian politicians but a fortune for most of the country.
Mr Buhari is the first opposition candidate to win a national election.
The former military ruler was elected in March largely on a promise to tackle corruption and insecurity.
Corruption is a major problem in Africa’s biggest economy and last month, Mr Buhari said that $150bn (£100bn) was missing from state coffers.
Vice-President Yemi Osinbajo, a successful lawyer and pastor at one of Nigeria’s biggest churches, is considerably wealthier.
Mr Shehu said in a statement Mr Osinbajo had $1.4m (£900,000) in his bank accounts.
In his declaration of assets, Mr Osinbajo also revealed that he owned a four-bedroom residence, a three-bedroom flat, a two-bedroom flat and a two-bedroom mortgaged property in Bedford, UK.
His political career started when he was appointed commissioner of justice in Lagos state in 2007 – a position he held for eight years.
The statement did not give the value of all the assets held by the president and the vice-president, saying the documents submitted to the Code of Conduct Bureau would be made public as soon as the verification process was completed.
The leaders are also required by law to declare their assets when they left office.
Late President Umaru Yar’Adua was the first Nigerian leader to declare his assets publicly.
He was reported to be worth $5m (£3.5m) when the declaration was made in 2007.