The attack in the capital and another in the northern city of Mazar-i-Sharif came a day after an international meeting in Germany aimed at charting a course for Afghanistan, 10 years after US-led forces drove the Taliban from power.
The Kabul blast alone killed at least 54 people, in the deadliest strike on the capital in three years, which President Hamid Karzai said was the first "terrorist" act on an important holy day.
NATO also condemned the attacks while the Taliban did not claim responsibility and instead denounced them as "inhumane" and blamed the bloodshed on the "invading enemy."
"I was there watching people mourning when there was suddenly a huge explosion," witness Ahmad Fawad said.
"Some people around me fell down injured. I wasn't hurt, so I got up and started running. It was horrible," he said.
Men and women in the scene sobbed as they surveyed the carnage, and screamed slogans denouncing Al-Qaeda and the Taliban.
A young girl, dressed in a green shalwar kameez smeared in blood, stood shrieking, surrounded by the crumpled bodies of slain children.
"There was a huge bang close to where I was standing, I felt a pain in my legs and hands and fell down. I saw a lot of people covered in blood around me," he said.
Health ministry spokesman Ghulam Sakhi Kargar Noorughli told AFP that 54 were dead in the Kabul attack and another 150 wounded.
Separately, four people were killed in Mazar-i-Sharif when another blast struck a shrine in the northern city. It was not immediately clear whether Shiites were the target.
The explosion was caused by a bicycle bomb, said Lal Mohammad Ahmadzai, a police spokesman for northern Afghanistan, adding that another four people were wounded.
During the 10-day Ashura ceremonies, which peaked on Tuesday, Shiites beat themselves with knives and chains in religious fervor as they mark the seventh-century killing of a grandson of the Prophet Mohammed.
Shiites were banned from marking Ashura in public under the Taliban.
An Afghan security official speaking on condition of anonymity said it was believed that the bomber at the Kabul shrine had arrived with a group of Shiite pilgrims from Logar province, south of Kabul.
Another security official said the capital was now on high alert, and extra security forces has been deployed in case of any follow-up attacks.
Kabul has been hit by an increasing number of spectacular attacks in 2011, including the September assassination of former president and peace envoy Burhanuddin Rabbani at his home, which hit hard any hopes for Taliban reconciliation.
In the southern city of Kandahar, the Taliban's heartland, police said another five people were wounded by a motorcycle bomb but it was not connected to Ashura.
The blasts came the day after delegates at the Bonn conference agreed to extend international support for Afghanistan to 2024 following the scheduled withdrawal of all foreign combat troops by the end of 2014.
Pakistan and the Taliban - both seen as pivotal to ending Afghanistan's long war - boycotted the talks, undermining already modest hopes for progress.
Karzai, who is still in Germany following the Bonn conference, appealed to Pakistan saying it had "a very important role to play in the peace process in Afghanistan."
There are around 140,000 international forces in Afghanistan, most from the United States, fighting the Taliban-led insurgency.
Ashura marks the slaughter of Imam Hussein; the grandson of the Prophet Mohammed, near Karbala by armies of the caliph Yazid in 680 AD (CE).
Tradition holds that the revered Imam was decapitated and his body mutilated. His death was a formative event in Shiite Islam.
On Monday, at least 28 people were killed and 78 wounded in a wave of bomb attacks in central Iraq against Shiite pilgrims making their way to Karbala.