Some aspects of yoga contain Hindu devotional mantras
The top Islamic body in Indonesia has issued a fatwa banning Muslims from practising some aspects of yoga.
The Council of Ulemas (MUI) said exercises containing Hindu elements such as chanting were forbidden and could weaken the faith of Muslims.
The move follows a similar ruling by the religious authorities in Malaysia last year.
Such religious edicts are not legally binding in Indonesia, but most Muslims consider it a sin to ignore them.
Maruf Amin, chairman of the MUI, said some yoga exercises involved the reciting of Hindu religious mantras, something which is forbidden, or "haram", in Islam.
"Muslims should not practise other religious rituals as it will erode and weaken their Islamic faith," he told AFP.
But he said yoga could still be practised if it was purely as a sport or a means of exercise.
Indonesia is officially a secular state but about 90% of the country's 235 million people are Muslim.
Mr Amin said that if any Indonesian Muslims refused to follow the fatwa, they would be committing a sin.