According to a Chief Election Office spokesperson, eight of the 42 candidates who filed nomination papers yesterday were found to be invalid.
Candidates of both Congress and BJP were found to be valid, he said.
Congress' Shravan Kumar, Bhajanlal, Ramnarayan and Shivkant would be contesting against their BJP rivals Digamber Singh, Gangaram Koli, Sarla Devi Gena and Sandeep Sharma in Surajgarh, Weir, Nasirabad, and Kota (South) assembly constituencies respectively.
Bypolls were necessitated in the four assembly seats of Rajasthan as they fell vacant after the sitting MLAs were elected to Lok Sabha.