The agency won the pitch against the incumbent, OMD, and Total Media. The account includes media communications for the Science Museum, the Imax 3D cinema and the Dana Centre.
Initiative has been briefed to explore ways of positioning the museum differently from other London tourist attractions. While the account covers all media, Initiative will be looking to leverage opportunities across digital platforms.
Stephen Bromberg, the marketing and communications manager at the Science Museum, said: "We want to highlight the distinctive elements of the Science Museum and what makes us stand out in such a busy market."
Gary Birtles, the chief executive of Initiative UK, said: "We are absolutely thrilled to be working with the Science Museum. We believe our ideas and innovation are ideally matched with the Science Museum's position at the forefront of technology."