كتب : Hatem Maher
Giampaolo Pazzini, who joined Sampdoria from Fiorentina last month, put the visitors ahead after 10 minutes.
He latched onto a superb through pass from Antonio Cassano before beating Gianluigi Buffon at the near post.
Brazilian-born striker Amauri leveled the score two minutes past the hour mark with a diving header after connecting with Sebastian Giovinco's right-wing cross.
Juventus could have grabbed the lead on several occasions but saw two efforts by Pavel Nedved strike the woodwork.
A free-kick by Alessandro Del Piero was also denied by the bar.
Juventus remain second in the league table with 47 points, but could be leapfrogged by third-placed Milan (45), who face leaders and arch-rivals Inter (53) later in the day.
Elsewhere, AS Roma slumped to a 3-0 defeat to Atalanta.
A brace from Cristiano Doni and a Daniele Capelli goal condemned Luciano Spalletti's men to an embarrassing defeat.
In-form Romanian striker Adrian Mutu scored a second-half hat-trick as Fiorentina staged a remarkable comeback to draw 3-3 at 10-man Genoa.
Genoa led 3-0 until the hour mark before Mutu stole the show to take his tally to 11 league goals.
Watch Pazzini goal
Watch Amauri goal