A member of the Social Democratic Party (PSD), he has represented Maramureș County in the Chamber of Deputies since 2011.
[1] In August 2011, he contested a by-election for the Chamber of Deputies to replace Cătălin Cherecheș, who had vacated a seat when he was elected mayor of Baia Mare.
The election acquired national importance, because together with a similar vote in Neamț County, it marked the first electoral test of the Social Liberal Union (USL).
[3] In response, President Traian Băsescu, a PDL supporter, noted the narrowness of the victory, suggesting that "the USL is and will be an electoral failure".
[8][9] Selected as his party's candidate for the June 2016 local election,[10] Tătaru finished in third place, with 7.3% of the vote.