The Millers found themselves two down inside 20 minutes after goals from two ex-Accrington men did the damage.
Recent signing Jimmy Ryan was given too much space in midfield and fired over Conrad Logan from 25 yards and then Bobby Grant converted a penalty after being chopped down in the box as the League One side took full control.
The Millers improved after the break with Danny Schofield, Lewis Grabban and Adam Le Fondre going close, with Ryan Cresswell also having a point blank header saved. Grabban looked particularly impressive out on the right wing with a couple of intelligent runs as Rotherham continued their pre-season preps.
But boss Andy Scott will be left disappointed overall, despite the evident gulf between his side and last years relegated Championship visitors who gave the Millers little space to play their football with their quick pressing.
Team: Logan; Tonge, Brown, Cresswell, Newey; Grabban, Harrison, Pringle, Schofield (Evans 79); Le Fondre, Holroyd (Taylor ht). Subs: Warrington, Foster, Marshall.