AS Roma forward Bojan Krkic, foreground right, celebrates past teammate Francesco Totti
Newly signed forwards Bojan Krkic and Pablo Osvaldo scored in the 20th and 31st minutes Saturday and surprise starter Fabio Simplicio sealed the match in the 81st after German Denis had pulled one back for Atalanta in the 48th.
Having been eliminated from the Europa League by Slovan Bratislava to open the season and then gone winless in its first three Serie A matches, Roma has now won two straight.
The victory drew Roma level with league leaders Juventus and Udinese with eight points each, although Juventus still leads on goals scored.
Atalanta is four points back, having begun the season with a six-point penalty from the latest match-fixing scandal.