The conservation body, which maintains historical sites across the country and is backed by the Department for Culture, Media and Sport, has sent out a tender document for both its above- and below-the-line accounts. Its contract with CHI recently expired.
The aim of the statutory review is to appoint a single agency to handle all aspects of the business. It is not known whether CHI will repitch.
Most of English Heritage's marketing is below-the-line, with an annual spend of about £1m. A spokeswoman said the organisation is not planning a budget increase.
English Heritage will continue its below-the-line focus, including sales promotion work to promote its membership scheme, which has more than 500,000 members.
The successful agency will work with English Heritage's design, print and online roster agencies. Last year it appointed Box New Media to handle its digital marketing.