The law was ratified by Kano governor Umaru Ganduje who warned kidnappers to stop or face the penalty.
“The law provides for the death sentence for kidnappers who abduct and kill their victims, while kidnappers who abduct but did not kill their victims, if apprehended and found culpable, would be jailed for life,” according to a statement issued by government spokesman Salihu Tanko Yakassai.
Wednesday’s statement also called on kidnappers and other criminal elements to turn in their weapons to the security agencies in exchange for a state pardon.
Kidnapping has become a national security headache across Nigeria.
At least nine states in the country’s southern region — where kidnapping is a thriving business among organized gangs — have laws prescribing the death penalty for the crime since 2013.
However, Kano has become the first state in the country’s north to roll out capital punishment for kidnapping. Kogi, in the north-central region, passed a similar law previously but it has not yet been ratified.
A bill does not become a law until assented to by the executive.
Human rights campaigners are generally opposed to capital punishment for any crime, insisting the measure does not guarantee a crime-free society.