Two men have been charged in connection with the arrests in Northern Ireland last night as part of a major police investigation into child pornography.
The men were charged with possession and making of indecent images of children.
Another five people were released on police bail pending further investigations.
The seven were arrested last night following a series of searches as part of a Police Service of Northern Ireland on going operation dating back several years.
A significant number of premises were searched right across Northern Ireland and a quantity of computer hard drives and other materials taken away for examination, said a police spokesman.
The seven people detained, all believed to be males, were being questioned at the PSNI's Serious Crime Suite in Antrim.
The spokesman said: "This is part of a major crime investigation led by the PSNI Care Unit into the possession and production of indecent images of children on the Internet."
He said the PSNI was committed to protecting children from sex offenders who used the Internet.
The operation was the result of a close working relationship with the Child Exploitation and Online Protection Centre, which forms a part of the new Serious and Organised Crime Agency in the UK.
The arrest and seizure operation was the latest phase of Operation Ore, which was launched in 2002 by the PSNI against child Internet pornography.