Player sales, most notably the £2.5million transfer of striker Craig Mackail-Smith to Brighton, are the main reason for the £3,619,719 profit.
The figure represents a huge improvement on the previous year, when Posh recorded a loss of £2.775,205.
The directors' report which accompanies the accounts suggests that player sales, along with the club maintaining its npower Championship status, is crucial to Peterborough's future financial well-being.
The accounts also confirm that Posh remain indebted financially to chairman Darragh MacAnthony.
"The creditable balance is mainly due to the considered transfer movement with this being essential to the future long-term sustainability of the football club," read the report.
"The directors run the company positively and prudently. Budgets and projections indicate that for the current season the company expects to break even, prior to any player transfers.
"The club also continues to invest in its first-team playing squad with the aim of providing a competitive team to maintain its current position in the second tier of English football. This continuing commitment is underpinned by the positive support of the chairman which also encompasses the new stadium, planning and development.
"The directors consider that the principle challenge facing the company is the performance and divisional status of Peterborough United Football Club. The implications this has on the club's ability to generate revenue streams are significant. In light of this risk, the company remains dependent on its parent company, DMA Holdings S.A."