He was accompanied by his father, Shiv Sena president Uddhav Thackeray, and mother Rashmi while filing nomination papers.
Marathas, a politically influential community that constitutes around 30 per cent of the state's population, have been demanding 16 per cent reservation in government jobs and education.
Raking up the December 16 gang rape case and the infamous Tandoor murder case, Narendra Modi on Friday attacked Sonia Gandhi over the issue of security of women and said women are not even safe in the Congress.