Estelle Hughes, who joined from the BBC as CITV head of programming in 2003, will leave at the end of the month.
Hughes' ITV1 duties will be taken on by director of factual and daytime Alison Sharman. Digital channels programming chief, Steven Andrew, will be responsible for the CITV channel.
Hughes' departure comes amid speculation that ITV is planning to reduce its content for children on ITV1 from eight hours to as little as two hours per week, in a bid to claw back lost advertising revenue with higher rated shows.
The broadcaster hopes to transfer a large slice of ad revenues to the digital channel, which launched in March.
ITV would need approval from Ofcom but has previously been successful in cuttings its news and regional content.
Ofcom is expected to introduce sweeping restrictions on advertising of junk food next month, which would limit advertising on all children's channels.
Hughes' ITV1 duties will be taken on by director of factual and daytime Alison Sharman. Digital channels programming chief, Steven Andrew, will be responsible for the CITV channel.
Hughes' departure comes amid speculation that ITV is planning to reduce its content for children on ITV1 from eight hours to as little as two hours per week, in a bid to claw back lost advertising revenue with higher rated shows.
The broadcaster hopes to transfer a large slice of ad revenues to the digital channel, which launched in March.
ITV would need approval from Ofcom but has previously been successful in cuttings its news and regional content.
Ofcom is expected to introduce sweeping restrictions on advertising of junk food next month, which would limit advertising on all children's channels.