Counting of votes will take place on November 24.
The two Lok Sabha seats where polls will be held are Ratlam (Madhya Pradesh) and Warangal (Telangana).
The Legislative Assembly seats are Lohardaga (Jharkhand), Devas (Madhya Pradesh), Thangmeiband and Thongju in Manipur, Aizawl North in Mizoram and Nongstoin in Meghalaya.
The seats have become vacant in the last six months due to various reasons including death of sitting legislators.
An EC statement said the model conduct of conduct on these seats has come into force with the declaration of polls.