Official MoD figures showed a total of £287,809,049 has been paid out in bonuses to civil servants since 2003, including more than £47 million this year.
Bereaved families said the bonuses were "absolutely disgusting" while troops were "making do" in Afghanistan.
Hazel Hunt, whose son died in August, said it was "obscene" that troops were being short-changed.
Private Richard Hunt was injured following an explosion while on vehicle patrol for the 2nd Battalion the Royal Welsh in Helmand Province. The 21-year-old from Abergavenny, South Wales, died in hospital two days later.
Mrs Hunt said: "I would take great exception to bonuses paid for 'exceptional performance'.
"They are not delivering and I think it is obscene they have got such bonuses while our troops are being short changed; not only in equipment but also in the fact that my son was barely on £17,000 a year.
"I think it is obscene, I really do, especially in the current climate with the recession and ordinary people losing their houses, including troops."
Phil Cooper - whose son received £200,000 in compensation for injuries received in Iraq - said it was "absolutely disgusting that they can do this from the safety of their armchairs".
Jamie, then 18, became the youngest soldier to be injured in the conflict in 2006.
His father said he was "laughing with astonishment" at the revelations.
Mr Cooper, 50, from Bristol, said the MoD's performance bonuses were unacceptable when troops were dying in Afghanistan and lacked equipment.
He said: "I find it ludicrous. It makes me angry that they are being paid £47 million to pat themselves on the backs."
Graham Knight, whose son Sergeant Ben Knight was killed when an RAF Nimrod exploded in mid-air over Helmand province on September 2 2006, added that news of the bonuses "beggars belief".
He said the pay-outs were "an insult" to the forces "making do" in Afghanistan.
The MoD said the bonuses - going to around 50,000 staff - would average less than £1,000 this year. But some senior officials may be receiving as much as £8,000, according to reports.
The figures emerged in a written reply from defence minister Kevan Jones to shadow defence secretary Liam Fox.
Mr Jones revealed that in the seven months from April to October this year, MoD staff received bonuses totalling £47,283,853. MoD sources said the majority of bonuses are handed out in August, so the figure is unlikely to rise by much over the remaining five months of the financial year.
The figure was down on the £52,984,656 paid out in 2008/09, but higher than the previous year's £46,103,238 and almost double the bonuses totalling £24,866,213 paid out in 2003/04.
Dr Fox has promised to cut 25 per cent from the cost of running the MoD, largely by reducing its headcount of 85,000 civil servants - one for every two active troops in the armed forces.
"Many in the armed forces will be aghast that bonuses are being paid on the basis of 'outstanding performance'," he told the Daily Telegraph.
"This will only increase the view that the armed forces and the MoD administration are hugely out of balance."
An MoD spokesman said: "These pay awards are met from within salary budget and have no impact on the operational or equipment budget.
"Pay awards were given to around 50,000 civil servants resulting in an average payment of less than £1,000.
"The vast majority of these awards were paid in August as part of previously agreed pay deals, so we are not expecting this year's total to increase significantly."
The lowest-paid Army privates earn £16,681 a year, with a six-month tax-free operational allowance of £2,380 if they are posted to Afghanistan.
Comments