The comments came as part of a speech to a ministerial meeting of the Non-Aligned Movement.
"We have reiterated that we are willing to talk about everything with the United States, in equality of conditions, but not to negotiate our sovereignty, nor our political and social system, the right to self-determination, nor our internal affairs," Castro said.
He said Cuba "has not imposed sanctions against the United States ... and therefore it is not Cuba that has to make gestures".
The last time Castro offered to discuss a wide range of topics with the US was on April 16.
He said then that discussion topics could include political prisoners - whom Cuba views as "mercenaries" in the service of the US - as well as democracy and freedom of the press.
The Obama administration greeted those comments as an important gesture, but Raul Castro's older brother, Fidel Castro, the former Cuban leader, wrote a few days later that the words had been "misinterpreted".
Fidel Castro indicated that Cuba had no intention of making concessions to Washington.
Cuban and US officials have begun informal talks in Washington to explore ways of improving relations that have been hostile since Fidel Castro took power in a 1959 revolution.