B flavor tagging is essential for analyses which require identification of the flavor of a 
neutral B meson at production, whether it comprised of a b-quark meson or an anti-b quark 
meson.  Flavor tagging is used in Bd and Bs mixing measurements, and CP violation studies. 
The flavor tagging at Tevatron, which is a hadron collider, is difficult due to large 
background and underlying events. Various techniques, like neural network and likelihood 
methods are therefore used to identify the flavor of the neutral B meson. 

The decision from various methods is combined and the Bd mixing measurement is performed 
to check the flavor tagger and do the tagger calibration for taggers which rely on decay 
products of the opposite B meson. Taggers which rely on fragmentation tracks around the 
produced B meson, are calibrated separately for Bs and Bd mesons. The calibration provides 
an optimal tagger performance on an event basis. The techniques developed at CDF and D0 
experiments at Tevatron, and its calibration using Bd and Bs decay samples is discussed.