Deputy Chief Justice Raymond Zondo said the law banning marijuana use by adults was unconstitutional.
The unanimous judgment decriminalises adults smoking cannabis at home and growing enough for personal consumption.
Last year, the Western Cape High Court decriminalised the use of marijuana at home.
But several government ministries – the justice, police, health and trade – challenged the ruling. They argued that it was not in line with the constitution, saying cannabis is more harmful to users than tobacco and alcohol. – BBC