Jun 8, 2007
The BBC's Umaru Fofana in Sierra Leone says girls as young as 11 are often married off to wealthy men but this is now banned until they are 18 years old.
However, the press and public were asked to leave parliament during the debate on female genital mutilation.
When they were allowed back, the section on FGM had been removed.
The local representative of UN children's agency Unicef said the passing of the bill was the best day for Sierra Leone's children since the end of the civil war.
But campaigners are not happy that FGM was not banned.
Senior MP Alassan Fofana told the BBC that there was a general consensus in parliament not to outlaw FGM.
He said that measures had been introduced to control it and pointed out that this was more than previous parliaments had done.
"They were afraid to be tagged as calling for a ban on FGM. For a lot of people, this would have cost their political career," he said.
Last year, a woman from Sierra Leone successfully claimed asylum in the UK on the basis that she feared being forcibly circumcised - a decision condemned by the Sierra Leone government.
Up to 90% of women have faced the procedure in the West African country, which sees part or all of the clitoris surgically removed, often resulting in reduced or no sexual feeling.
FGM is practised in many West, North and East African countries.
One Sierra Leone girl nevertheless told the BBC that the new law would improve her life.
"I'm more privileged than my mum - she was forced into marriage at an early age. At least I can decide for myself how to live my life without my parents interfering," she said.