Bukharov joins big-spending Zenit
Zenit said on their website that the big striker had signed a four-year contract.
The transfer fee was not disclosed but Russian media put the deal at around 12 million euros.
Bukharov, 25, had been at Rubin since 2004, helping them to two Russian league titles in the past two seasons.
Zenit, backed by Russian energy giant Gazprom and coached by Italian Luciano Spalletti, were looking to add extra muscle to their attack ahead of their European campaign.
The Russians, who lifted the UEFA Cup in 2008, face Romania's Unirea Urziceni in the Champions League third qualifying round later this month.