On a tip-off, a team of Ujjain police apprehended the suspected racketeers from a house located at Maxi Road area here on Friday night, police said.
Police recovered betting slips to the tune of Rs 50 lakh, a laptop, 21 cellphones and two registers from their possession.
"The mobile phones of the four arrested persons are being examined to find out the places they are connected with," Ujjain SP Anurag Kumar said without elaborating.
The arrested persons were identified as Parth Nigam, Arush Shreeram Sharma -- both from Ujjain -- Deepak Tiwari from Indore and Ankur Sharma belonging to Firozabad in Uttar Pradesh, police said.