THE HAGUE, Netherlands — Former Bosnian Serb leader Radovan Karadzic appeared at the United Nations’ Yugoslav war crimes tribunal for the first time today, telling the judge he would defend himself against charges of genocide and crimes against humanity.

Appearing older and thinner than during the Bosnian war and shorn of the long white hair and bushy beard that once disguised him, Mr. Karadzic refused to enter pleas on the 11 charges against him or have his full indictment read to him.

He told the court he would act as his own lawyer.

“I have an invisible adviser but I have decided to represent myself,” he calmly told the presiding judge, Alphons Orie.

Mr. Karadzic, who smiled at times during the hearing, listened intently as Judge Orie read a summary of the indictment in which prosecutors allege Mr. Karadzic masterminded atrocities, including the Srebrenica massacre and siege of Sarajevo during Bosnia’s 1992-95 war.

“I am not interested in having someone else read the indictment to me,” he said. “I would rather receive the new indictment that has been announced and have sufficient time to study it and then have my initial appearance for that and enter my plea.”

A prosecutor, Serge Brammertz, confirmed that he was planning to amend the indictment but gave no further details.

Judge Orie scheduled a new hearing on Aug. 29 at which Mr. Karadzic will have to enter pleas. If he does not, the court will enter not guilty pleas for him.

Mr. Karadzic then identified himself by stating his name, date, and place of birth. He also gave his most recent address as his family home at Pale, Bosnia, but also gave the address of the apartment in Belgrade where he was living under an assumed name before his address.

When Judge Orie asked him if his family knew where he was being held, Mr. Karadzic replied “I do not believe there is anyone who does not know that I am in the detention unit.”