A function was organised at the Shiv Sena Bhawan in Mumbai where Uddhav was appointed the party president.
The decision was officially announced after the party's national executive meeting on Wednesday where the members anointed Uddhav, 52, as the new party president.
Even after Uddhav taking over as president, the late Sena patriarch will continue to be known as 'pramukh' (supremo), a party official said.
As a part of the birth anniversary celebrations at Lalbaug, the Shiv Sainiks are distributing Chinese retractable knives to women of the city so that they can protect themselves.
"Bal Thackeray used to say women should prefer a Rampuri in their purse rather than a lipstick," the right wing Shiv Sena's South Region head Ajay Chaudhry said when asked about the inspiration behind the plan. "This government has failed to provide security to women so we are distributing these knives to empower them," he added.
Sena MP Bharat Raut had, however, told NDTV on Tuesday that "this is something that's being done at a shakha (block) level." He said he was not aware if this had the support and blessings of Sena's top leadership.
Uddhav Thackeray along with actor Amitabh Bachchan is also expected to launch the 'Swacch Mumbai Prabodhan Abhiyan' - a drive aimed at cleaning Mumbai's slums at around 3 pm today. He will also inaugurate the virtual classrooms of the Brihanmumbai Municipal Corporation or the BMC.
(With inputs from IANS)