The Millers came from a goal down in the second half with goals from Ryan Cresswell and Adam Le Fondre, after Neil Mackenzie's strike had put the hosts infront.
In the opening 45 minutes Mackenzie had given the home side the lead with a drilled shot, with Ronnie Moore giving sub opportunities to trialist Jeremiah Ani and youth team prospect Ollie Banks.
Jamie Green hobbled off with a groin injury leaving Danny Harrison to move to right-back with Grant Darley coming on in midfield.
And Darley produced a fine display after the break, as he crossed for Cresswell to powerfully head home and then set up Le Fondre a minute later with a by-line cross which was converted from a couple of yards.
Dale Tonge and Johnny Mullins again missed out through injury, with Tonge aggravating his metatarsal in training on Friday as the team finished with a stronger second half display which will provide a little encouragement.
Tamworth: Hamilton; Tait, Marshall (Rowe 82), Wylde, Bradley (Mitchell 66), Rodman (Fairclough 75), Perry, Mackenzie, Thomas (Farrell 75), Sheridan (Lyttle 68), Barrow.
Rotherham: Warrington; Green (Darley 39), Cresswell, Ashworth, Newey, Law, J.Taylor, Harrison, Ellison, Elliott (Ani HT), Le Fondre (Warne 75).
Subs not used: Marshall, Annerson, Banks.
Crowd: 456