Honours were even at Millmoor as Cardiff struggled to come to terms with their return to Division One football.
Rotherham striker Alan Lee, a summer transfer target for the Bluebirds, was the star of the show and a constant threat to the
The home team carved out the clearest chances, but Cardiff showed grit and resilience to absorb Rotherham's incessant aerial
Both sides struggled to come to terms with the blistering heat and will have been satisfied to open their season with a point.
After a slow start, the Millers slowly began to assert their authority and only a stunning save from goalkeeper Neil Alexander denied Mark Robins a ninth-minute strike.
The Bluebirds gradually found their feet, Chris Barker spurning a golden chance and Rob Earnshaw going close with a deft chip.
The Millers rallied again in the second half, Lee going close on the hour mark with a swivel shot.
Rotherham were now well on top and defender Martin McIntosh was left cursing his luck when his thumping header off Darren Garner's inswinging corner went inches wide of the right-hand post.
However, Cardiff once again proved their appetite for a battle and held out to gain a valuable point.
Rotherham: Pollitt, Shaun Barker, Swailes, McIntosh, Minto,
Sedgwick, Talbot, Daws, Garner, Robins, Lee. Subs: Jones,
Byfield, Hurst, Monkhouse, Richard Barker.
Cardiff: Alexander, Weston, Vidmar, Gabbidon, Barker, Bonner, Boland, Kavanagh, Robinson, Campbell, Earnshaw. Subs: Collins, Maxwell, Whalley, Bowen, Margetson.
Referee: Peter Walton (Northamptonshire)