According to the Foreign Office, President Zardari will be accompanied by the Foreign Minister Hina Rabbani Khar and Foreign Secretary Jalil Abbas Jelani.
The President will address the Expanded Isaf Meeting of Nato and also meet various heads of state.
The FO said president Zardari was given invitation to the Chicago Summit by Nato Secretary General Andres Fogh Rasmussen.
The May 20-21 summit will be the first Nato summit in US in 13 years and the first held outside Washington. It also will be the biggest Nato summit in history, with more than 60 countries and organisations represented.