The company is to reduce its current headcount of 1,000 staff by up to 150 posts. It will offer voluntary redundancies and consult staff on other ways to minimise compulsory job losses.
The broadcaster said the move was part of its "ongoing efficiency drive" in response to an advertising downturn that is forecast to reduce its budgeted revenues by £50m this year. Channel 4 said it is performing in line with the market, which is down 5%.
The move, announced to staff today, also involves cutting the group's programming spend by more than £25 million in 2008 against a budget of just over £600m. In 2007, the group spent £615m.
Channel 4 said it has identified a further £25m of savings in 2008 from all other areas including marketing, new business investment, new media and general overheads. It is planning a further £50m reduction in its cost base in 2009.
Andy Duncan, chief executive, said: "Channel 4 has outperformed its competitors in recent years but the economic downturn is now affecting the entire media industry. Our objective as a public organisation is to operate at break even while maximising creative investment."
"With revenues falling, we've no alternative but to cut costs. My particular regret is the impact of these job losses amongst our skilled and dedicated workforce."
Media regulator Ofcom has pronounced that Channel 4 is facing an annual deficit of up to £100m by 2012 as it prepares for digital switchover. This excludes the cost of the additional public service commitments outlined in its 'Next on 4' strategic blueprint, which Channel 4 estimates at more than £50m.
Channel 4 has already reduced its headcount by 200 to just below 1,000 in the last 18 months, bringing it down to below 2001 levels.