Staff at RAF Kinloss have been told that the Moray base is to lose one of its three squadrons by 1 April, 2005.
RAF Kinloss' three Nimrod squadrons will be reduced to two
Three squadrons of Nimrod aircraft are currently stationed at the base. The number of crews will be reduced from 24 to 20 as part of a defence review.
The base commander, Group Captain Chris Birks, said an RAF board would decide which squadron is to go.
It was announced in September that 390 jobs would be lost at nearby RAF Lossiemouth as part of the same review.
Between them, the two Scottish bases employ nearly 5,000 people and inject almost £100m into the Scottish economy.
Defence White Paper
Cpt Birks said: "In order to meet the proposed reduction in aircrew recently announced in the Defence White Paper, we need to reduce our operational squadrons to two large squadrons of 10 crews rather than the present three squadrons with eight crews.
"This will take place on April 1 2005.The decision as to which squadron to disband will be made by the RAF board."
Local campaigner Rick Walker urged the MoD to clarify its plans for the remaining fleet.
"At least that would give the local community a chance to prepare for the economic impact of closure," he said.
Moray SNP MP Angus Robertson accused Labour ministers of "running down" the armed forces at a time of global instability.
"Axing this RAF Kinloss squadron is the latest local military cutback forced by the government," he said.
"Within recent months, the MoD has announced nearly 400 job losses or relocation from RAF Lossiemouth, they are actively looking to run-down or close bases and now a local squadron is to go at RAF Kinloss.
"In Moray we need to concentrate our efforts in supporting the local airbases.
"They are vital for strategic reasons, are crucial for the local economy and highly significant in their contribution to the community in Moray."