Markelov, 34, who represented a family whose daughter was murdered by a Russian officer, was shot dead on Monday in downtown Moscow. Novaya Gazeta journalist Baburova, 25, who was with him, was wounded in the shooting and died in hospital later on Monday.
The incident occurred shortly after Markelov had given a news conference on the controversial early parole and release on January 15 of Yury Budanov, convicted in the summer of 2003 of strangling 18-year-old Elsa Kungayeva three years earlier and sentenced to 10 years in jail.
Investigators said they believe the killing of Markelov was connected to his professional activities.
Police said Baburova "became an accidental witness and victim in the crime." Media reports said, however Baburova had attempted to stop the killer, but he shot her in the head before making his escape.
Around 300 people, including relatives and colleagues, with well-known Russian lawyer Genry Reznik among them, attended the funeral of Markelov at the Ostankino Cemetery in northeast Moscow.
The ceremony was held in silence as people laid flowers and wreaths to mark their respect.
"The name of this very young man, Stanislav Markelov, will be immortalized in the history of the Russian advocacy," Reznik told journalists, adding that Markelov "was a brave man who was unaware of danger."
A ceremony to Baburova was held in a Moscow clinic. The funeral will be held in her home city of Sevastopol, southern Ukraine, on January 26. Ukrainian President Viktor Yushchenko has expressed his condolences to the student journalist's parents saying "she became a victim of insolent criminals who should be identified and be severely punished."
The murder case has been passed to the Russian Investigation Committee. According to the committee chairman, Alexander Bastrykin, the case will be complicated by the number of links the victims are reported to have had.
Markelov had appealed against the early release of Budanov and claimed the former army officer "was still threatening the Kungayev family."
Meanwhile, Budanov flatly denied the allegations that he had masterminded the killing of the lawyer. "Somebody wants tragic sensations. I think first of all about those who seek to drive a wedge between Russians and Chechens," he told popular Russian tabloid Komsomolskaya Pravda.
