His attorneys planned to make a statement later Wednesday morning.
The grand jury charged Castro with two counts of aggravated murder related to one act, saying he purposely caused the unlawful termination of one of the women's pregnancies. He also was indicted on 139 counts of rape, 177 counts of kidnapping, seven counts of gross sexual imposition, three counts of felonious assault and one count of possession of criminal tools.
The 142-page indictment covers only the period from August 2002, when the first victim disappeared, to February 2007. Prosecutors say the investigation will continue and they are leaving the door open to pursuing a death penalty case against Castro.
News that the women had been found alive electrified the Cleveland area, where two of the victims were household names after years of searches, publicity and vigils. But elation soon turned to shock as allegations about their treatment began to emerge.
The indictment against Castro alleges he repeatedly restrained the women, sometimes chaining them to a pole in a basement, to a bedroom heater or inside a van. It says one of the women tried to escape and he assaulted her with a vacuum cord around her neck.
Later, he moved them to upstairs rooms where they were kept as virtual prisoners, according to investigators.
All the while, Castro continued driving a school bus and playing bass in local bands, with fellow musicians saying they never suspected a thing. He was fired as a bus driver last fall after leaving his bus unattended for several hours.
Castro has been held on $8 million bail, which was continued. Last week he was taken off suicide prevention watch in jail. Cuyahoga County jail logs show him spending most of his time sleeping, lying on his bunk, watching TV and occasionally drawing.
Castro was arrested May 6, shortly after one of the women broke through a door and yelled to neighbors for help.
She told a police dispatcher in a dramatic 911 call: "Help me. I'm Amanda Berry. I've been kidnapped, and I've been missing for 10 years, and I'm, I'm here, I'm free now."
The women -- Berry, Gina DeJesus and Michelle Knight -- disappeared separately between 2002 and 2004, when they were 14, 16 and 20 years old. Each said they had accepted a ride from Castro, who remained friends with DeJesus' family and even attended vigils over the years marking her disappearance.
The women haven't spoken publicly since their rescue.
Berry, 27, told officers that she was forced to give birth in a plastic pool in the house so it would be easier to clean up. Berry said she, her baby and the two other women rescued with her had never been to a doctor during their captivity.
Knight, 32, said her five pregnancies ended after Castro starved her for at least two weeks and "repeatedly punched her in the stomach until she miscarried," authorities said.
She also said Castro forced her to deliver Berry's baby under threat of death if the baby died. She said that when the newborn stopped breathing, she revived her through mouth-to-mouth resuscitation.
The picture of Castro as a friendly musician began to erode soon after the women were freed, as family members told of a man who terrorized his common-law wife, beating her and locking her in an apartment and the same house where the women were later kept.
Castro's two brothers were arrested the same day but were released at a hearing a few days later after it was determined they weren't aware of the activities their brother is accused of. They denounced him in later interviews.
The Associated Press does not usually identify people who may be victims of sexual assault, but the names of the three women were widely circulated by their families, friends and law enforcement authorities for years during their disappearances and after they were found.