Goals from Carlton Morris and Michael Ihikewe cancelled out Kelechi Iheanacho's double at a sodden AESSEAL New York Stadium.
Paul Warne's men, who also drew with West Brom in midweek, now have a full week of training before the big League One kick-off at AFC Wimbledon next week and will go into that clash with confidence.
They fell behind in the 12th minute as Iheanacho fired home and goalkeeper Daniel Iversen, playing against his parent club, made a number of saves to keep the score at one.
The Millers were level seven minutes before the break as Morris clipped home nicely after fine work from Kyle Vassell.
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Iheanacho's second put Leicester back in front in the 72nd minute when he capitalised on Ihiekwe's error, but the Millers defender made up for his slack work at the other end.
He earned a draw for Warne's men when he converted at the second attempt after an original header hit the post.
Rotherham: Iversen (Price 65); Olosunde, Ihiekwe (Cooper 81), Robertson (Hinds 81), Mattock (Wood 65); MacDonald, Barlaser (Wiles 60), Crooks (Lindsay 60); Vassell (Kayode 71), Morris (Ladapo 56), Smith (Proctor 60).
Leicester: Ward; Justin, Morgan, Soyuncu, Fuchs; Silva (Ghezzal 57); Mendy (Amartey 50), King; Gray, Iheanacho, Barnes (Muskwe 85). Subs not used: Jakupovic, Ughelumba, Moore.